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class="theme-doc-sidebar-item-category theme-doc-sidebar-item-category-level-1 menu__list-item menu__list-item--collapsed"><div class="menu__list-item-collapsible"><a class="menu__link menu__link--sublist menu__link--sublist-caret" role="button" aria-expanded="false" href="/docs/core-concepts/basic-internationalization-principles">Core Concepts</a></div></li></ul></nav></div></div></aside><main class="docMainContainer_fiOQ"><div class="container padding-top--md padding-bottom--lg"><div class="row"><div class="col docItemCol_qWUW"><div class="docItemContainer_SZEY"><article><nav class="theme-doc-breadcrumbs breadcrumbsContainer_UQw4" aria-label="Breadcrumbs"><ul class="breadcrumbs" itemscope="" itemtype="https://schema.org/BreadcrumbList"><li class="breadcrumbs__item"><a aria-label="Home page" class="breadcrumbs__link" href="/"><svg viewBox="0 0 24 24" class="breadcrumbHomeIcon_kXUq"><path d="M10 19v-5h4v5c0 .55.45 1 1 1h3c.55 0 1-.45 1-1v-7h1.7c.46 0 .68-.57.33-.87L12.67 3.6c-.38-.34-.96-.34-1.34 0l-8.36 7.53c-.34.3-.13.87.33.87H5v7c0 .55.45 1 1 1h3c.55 0 1-.45 1-1z" fill="currentColor"></path></svg></a></li><li class="breadcrumbs__item"><span class="breadcrumbs__link">Getting Started</span><meta itemprop="position" content="1"></li><li itemscope="" itemprop="itemListElement" itemtype="https://schema.org/ListItem" class="breadcrumbs__item breadcrumbs__item--active"><span class="breadcrumbs__link" itemprop="name">Message Declaration</span><meta itemprop="position" content="2"></li></ul></nav><div class="tocCollapsible_Qhn1 theme-doc-toc-mobile tocMobile_yzro"><button type="button" class="clean-btn tocCollapsibleButton_CEvK">On this page</button></div><div class="theme-doc-markdown markdown"><header><h1>Message Declaration</h1></header><p>While you can declare your messages using only <code>id</code>s, we highly recommend declaring <code>defaultMessage</code>s inline along with their usages because of the following reasons:</p>
<ol>
<li>Messages colocated with their usages become self-managed, as their usages change/removed, so are the messages.</li>
<li>Messages are highly contextual. We&#x27;ve seen a lot of cases where developers assume a certain grammar when they write their messages. Buttons/Call-To-Actions and labels are also translated differently.</li>
<li>Text styling is also dependent on the message itself. Things like truncation, capitalization... certainly affect the messages themselves.</li>
<li>Better integrations with toolchains. Most toolchains cannot verify cross-file references to validate syntax/usage.</li>
</ol>
<p>At a high level, formatjs messages use <a href="/docs/core-concepts/icu-syntax">ICU Syntax</a> with a couple of enhancements common in other message format such as <a href="https://github.com/projectfluent/fluent.js/" target="_blank" rel="noopener noreferrer">Fluent</a>. This section focuses on the actual supported ways of calling <code>formatjs</code> APIs so messages can be extracted.</p>
<h2 class="anchor anchorWithStickyNavbar_p9lz" id="using-imperative-api-intlformatmessage">Using imperative API <code>intl.formatMessage</code><a href="#using-imperative-api-intlformatmessage" class="hash-link" aria-label="Direct link to using-imperative-api-intlformatmessage" title="Direct link to using-imperative-api-intlformatmessage">​</a></h2>
<div class="language-tsx codeBlockContainer_bLi2 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_KmF9"><pre tabindex="0" class="prism-code language-tsx codeBlock_TJkF thin-scrollbar" style="color:#bfc7d5;background-color:#292d3e"><code class="codeBlockLines_Dj5s"><span class="token-line" style="color:#bfc7d5"><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// Method must be exactly `intl.formatMessage`</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">intl</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">formatMessage</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">    description</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;A message&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// Description should be a string literal</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">    defaultMessage</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;My name is {name}&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// Message should be a string literal</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">    name</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> userName</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  </span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// Values should be an object literal, but not necessarily every value inside</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><br></span></code></pre><div class="buttonGroup_y8YM"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_nmJ9" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_wyV_"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_jM5N"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div>
<h2 class="anchor anchorWithStickyNavbar_p9lz" id="using-react-api-formattedmessage">Using React API <code>&lt;FormattedMessage/&gt;</code><a href="#using-react-api-formattedmessage" class="hash-link" aria-label="Direct link to using-react-api-formattedmessage" title="Direct link to using-react-api-formattedmessage">​</a></h2>
<div class="language-tsx codeBlockContainer_bLi2 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_KmF9"><pre tabindex="0" class="prism-code language-tsx codeBlock_TJkF thin-scrollbar" style="color:#bfc7d5;background-color:#292d3e"><code class="codeBlockLines_Dj5s"><span class="token-line" style="color:#bfc7d5"><span class="token keyword" style="font-style:italic">import</span><span class="token plain"> </span><span class="token imports punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token imports maybe-class-name">FormattedMessage</span><span class="token imports punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"> </span><span class="token keyword" style="font-style:italic">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;react-intl&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">;</span><span class="token tag punctuation" style="color:rgb(199, 146, 234)">&lt;</span><span class="token tag class-name" style="color:rgb(255, 203, 107)">FormattedMessage</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)">  </span><span class="token tag attr-name" style="color:rgb(255, 203, 107)">description</span><span class="token tag attr-value punctuation attr-equals" style="color:rgb(199, 146, 234)">=</span><span class="token tag attr-value punctuation" style="color:rgb(199, 146, 234)">&quot;</span><span class="token tag attr-value" style="color:rgb(255, 85, 114)">A message</span><span class="token tag attr-value punctuation" style="color:rgb(199, 146, 234)">&quot;</span><span class="token tag" style="color:rgb(255, 85, 114)"> </span><span class="token tag comment" style="color:rgb(105, 112, 152);font-style:italic">// Description should be a string literal</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)">  </span><span class="token tag attr-name" style="color:rgb(255, 203, 107)">defaultMessage</span><span class="token tag attr-value punctuation attr-equals" style="color:rgb(199, 146, 234)">=</span><span class="token tag attr-value punctuation" style="color:rgb(199, 146, 234)">&quot;</span><span class="token tag attr-value" style="color:rgb(255, 85, 114)">My name is {name}</span><span class="token tag attr-value punctuation" style="color:rgb(199, 146, 234)">&quot;</span><span class="token tag" style="color:rgb(255, 85, 114)"> </span><span class="token tag comment" style="color:rgb(105, 112, 152);font-style:italic">// Message should be a string literal</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)">  </span><span class="token tag attr-name" style="color:rgb(255, 203, 107)">values</span><span class="token tag script language-javascript script-punctuation punctuation" style="color:rgb(199, 146, 234)">=</span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)">    </span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)">      name</span><span class="token tag script language-javascript operator" style="color:rgb(137, 221, 255)">:</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"> userName</span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)">    </span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"> </span><span class="token tag script language-javascript comment" style="color:rgb(105, 112, 152);font-style:italic">// Values should be an object literal, but not necessarily every value inside</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)">  </span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)"></span><span class="token tag punctuation" style="color:rgb(199, 146, 234)">/&gt;</span><br></span></code></pre><div class="buttonGroup_y8YM"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_nmJ9" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_wyV_"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_jM5N"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div>
<h2 class="anchor anchorWithStickyNavbar_p9lz" id="using-vue-api--template-methods-such-as-formatmessage">Using Vue API &amp; template methods such as <code>$formatMessage</code><a href="#using-vue-api--template-methods-such-as-formatmessage" class="hash-link" aria-label="Direct link to using-vue-api--template-methods-such-as-formatmessage" title="Direct link to using-vue-api--template-methods-such-as-formatmessage">​</a></h2>
<div class="language-vue codeBlockContainer_bLi2 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_KmF9"><pre tabindex="0" class="prism-code language-vue codeBlock_TJkF thin-scrollbar" style="color:#bfc7d5;background-color:#292d3e"><code class="codeBlockLines_Dj5s"><span class="token-line" style="color:#bfc7d5"><span class="token plain">&lt;template&gt;</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  &lt;p&gt;{{ $formatNumber(3, {style: &#x27;currency&#x27;, currency: &#x27;USD&#x27;}) }}&lt;/p&gt;</span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">&lt;/template&gt;</span><br></span></code></pre><div class="buttonGroup_y8YM"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_nmJ9" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_wyV_"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_jM5N"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div>
<h2 class="anchor anchorWithStickyNavbar_p9lz" id="pre-declaring-using-definemessage-for-later-consumption-less-recommended">Pre-declaring using <code>defineMessage</code> for later consumption (less recommended)<a href="#pre-declaring-using-definemessage-for-later-consumption-less-recommended" class="hash-link" aria-label="Direct link to pre-declaring-using-definemessage-for-later-consumption-less-recommended" title="Direct link to pre-declaring-using-definemessage-for-later-consumption-less-recommended">​</a></h2>
<div class="language-tsx codeBlockContainer_bLi2 theme-code-block" style="--prism-color:#bfc7d5;--prism-background-color:#292d3e"><div class="codeBlockContent_KmF9"><pre tabindex="0" class="prism-code language-tsx codeBlock_TJkF thin-scrollbar" style="color:#bfc7d5;background-color:#292d3e"><code class="codeBlockLines_Dj5s"><span class="token-line" style="color:#bfc7d5"><span class="token keyword" style="font-style:italic">import</span><span class="token plain"> </span><span class="token imports punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token imports">defineMessage</span><span class="token imports punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token plain"> </span><span class="token keyword" style="font-style:italic">from</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;react-intl&#x27;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token keyword" style="font-style:italic">const</span><span class="token plain"> message </span><span class="token operator" style="color:rgb(137, 221, 255)">=</span><span class="token plain"> </span><span class="token function" style="color:rgb(130, 170, 255)">defineMessage</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  description</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;A message&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// Description should be a string literal</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">  defaultMessage</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;My name is {name}&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// Message should be a string literal</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain">intl</span><span class="token punctuation" style="color:rgb(199, 146, 234)">.</span><span class="token method function property-access" style="color:rgb(130, 170, 255)">formatMessage</span><span class="token punctuation" style="color:rgb(199, 146, 234)">(</span><span class="token plain">message</span><span class="token punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token plain"> </span><span class="token punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token plain">name</span><span class="token operator" style="color:rgb(137, 221, 255)">:</span><span class="token plain"> </span><span class="token string" style="color:rgb(195, 232, 141)">&#x27;John&#x27;</span><span class="token punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token punctuation" style="color:rgb(199, 146, 234)">)</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// My name is John</span><span class="token plain"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token plain"></span><span class="token tag punctuation" style="color:rgb(199, 146, 234)">&lt;</span><span class="token tag class-name" style="color:rgb(255, 203, 107)">FormattedMessage</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)">  </span><span class="token tag spread punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token tag spread operator" style="color:rgb(137, 221, 255)">...</span><span class="token tag spread" style="color:rgb(255, 85, 114)">message</span><span class="token tag spread punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)">  </span><span class="token tag attr-name" style="color:rgb(255, 203, 107)">values</span><span class="token tag script language-javascript script-punctuation punctuation" style="color:rgb(199, 146, 234)">=</span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">{</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)">    name</span><span class="token tag script language-javascript operator" style="color:rgb(137, 221, 255)">:</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"> </span><span class="token tag script language-javascript string" style="color:rgb(195, 232, 141)">&#x27;John&#x27;</span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">,</span><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag script language-javascript" style="color:rgb(255, 85, 114)">  </span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token tag script language-javascript punctuation" style="color:rgb(199, 146, 234)">}</span><span class="token tag" style="color:rgb(255, 85, 114)"></span><br></span><span class="token-line" style="color:#bfc7d5"><span class="token tag" style="color:rgb(255, 85, 114)"></span><span class="token tag punctuation" style="color:rgb(199, 146, 234)">/&gt;</span><span class="token plain"> </span><span class="token comment" style="color:rgb(105, 112, 152);font-style:italic">// My name is John</span><br></span></code></pre><div class="buttonGroup_y8YM"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_nmJ9" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_wyV_"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_jM5N"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div>
<div class="theme-admonition theme-admonition-caution admonition_FQKl alert alert--warning"><div class="admonitionHeading_o0VE"><span class="admonitionIcon_kLfP"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg></span>caution</div><div class="admonitionContent_M0jc"><p>We rely on AST to extract messages from the codebase, so make sure you call <code>intl.formatMessage()</code>, use our builtin React components, use our Vue methods or configure <code>--additionalFunctionNames</code>/<code>--additionalComponentNames</code> in our <a href="/docs/tooling/cli">CLI</a> properly.</p></div></div>
<div class="theme-admonition theme-admonition-caution admonition_FQKl alert alert--warning"><div class="admonitionHeading_o0VE"><span class="admonitionIcon_kLfP"><svg viewBox="0 0 16 16"><path fill-rule="evenodd" d="M8.893 1.5c-.183-.31-.52-.5-.887-.5s-.703.19-.886.5L.138 13.499a.98.98 0 0 0 0 1.001c.193.31.53.501.886.501h13.964c.367 0 .704-.19.877-.5a1.03 1.03 0 0 0 .01-1.002L8.893 1.5zm.133 11.497H6.987v-2.003h2.039v2.003zm0-3.004H6.987V5.987h2.039v4.006z"></path></svg></span>caution</div><div class="admonitionContent_M0jc"><p>You can declare a message without immediately formatting it with <code>defineMessage</code> and our extractor would still be able to extract it. However, our <a href="/docs/tooling/linter#enforce-placeholders">enforce-placeholders</a> linter rule won&#x27;t be able to analyze it.</p></div></div></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="row margin-top--sm theme-doc-footer-edit-meta-row"><div class="col"><a href="https://github.com/formatjs/formatjs/edit/main/website/docs/getting-started/message-declaration.md" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_iU4W" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_uQkO"><span class="theme-last-updated">Last updated<!-- --> on <b><time datetime="2025-02-09T06:06:18.000Z" itemprop="dateModified">Feb 9, 2025</time></b> by <b>SnowyOwl</b></span></div></div></footer></article><nav class="pagination-nav docusaurus-mt-lg" aria-label="Docs pages"><a class="pagination-nav__link pagination-nav__link--prev" href="/docs/getting-started/application-workflow"><div class="pagination-nav__sublabel">Previous</div><div class="pagination-nav__label">Application Workflow</div></a><a class="pagination-nav__link pagination-nav__link--next" href="/docs/getting-started/message-extraction"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">Message Extraction</div></a></nav></div></div><div class="col col--3"><div class="tableOfContents_VPeS thin-scrollbar theme-doc-toc-desktop"><ul class="table-of-contents table-of-contents__left-border"><li><a href="#using-imperative-api-intlformatmessage" class="table-of-contents__link toc-highlight">Using imperative API <code>intl.formatMessage</code></a></li><li><a href="#using-react-api-formattedmessage" class="table-of-contents__link toc-highlight">Using React API <code>&lt;FormattedMessage/&gt;</code></a></li><li><a href="#using-vue-api--template-methods-such-as-formatmessage" class="table-of-contents__link toc-highlight">Using Vue API &amp; template methods such as <code>$formatMessage</code></a></li><li><a href="#pre-declaring-using-definemessage-for-later-consumption-less-recommended" class="table-of-contents__link toc-highlight">Pre-declaring using <code>defineMessage</code> for later consumption (less recommended)</a></li></ul></div></div></div></div></main></div></div></div><footer class="footer footer--dark"><div class="container container-fluid"><div class="row footer__links"><div class="col footer__col"><div class="footer__title">Docs</div><ul class="footer__items clean-list"><li class="footer__item"><a class="footer__link-item" href="/docs/getting-started/installation">Getting Started</a></li><li class="footer__item"><a class="footer__link-item" href="/docs/polyfills">Polyfills</a></li><li class="footer__item"><a class="footer__link-item" href="/docs/intl-messageformat">Libraries</a></li><li class="footer__item"><a class="footer__link-item" href="/docs/tooling/cli">Tooling</a></li></ul></div><div class="col footer__col"><div class="footer__title">Community</div><ul class="footer__items clean-list"><li class="footer__item"><a href="https://stackoverflow.com/questions/tagged/formatjs" target="_blank" rel="noopener noreferrer" class="footer__link-item">Stack Overflow<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_MKBZ"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li><li class="footer__item"><a href="https://formatjs.slack.com/" target="_blank" rel="noopener noreferrer" class="footer__link-item">Slack<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_MKBZ"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li></ul></div><div class="col footer__col"><div class="footer__title">Social</div><ul class="footer__items clean-list"><li class="footer__item"><a href="https://github.com/formatjs/formatjs" target="_blank" rel="noopener noreferrer" class="footer__link-item">GitHub<svg width="13.5" height="13.5" aria-hidden="true" viewBox="0 0 24 24" class="iconExternalLink_MKBZ"><path fill="currentColor" d="M21 13v10h-21v-19h12v2h-10v15h17v-8h2zm3-12h-10.988l4.035 4-6.977 7.07 2.828 2.828 6.977-7.07 4.125 4.172v-11z"></path></svg></a></li></ul></div></div><div class="footer__bottom text--center"><div class="footer__copyright">Copyright © 2025 FormatJS. 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