BooleanArray

Boolean array.

Usage

var BooleanArray = require( '@stdlib/array/bool' );

BooleanArray()

Creates a boolean array.

var arr = new BooleanArray();
// returns <BooleanArray>

BooleanArray( length )

Creates a boolean array having a specified length.

var arr = new BooleanArray( 10 );
// returns <BooleanArray>

var len = arr.length;
// returns 10

BooleanArray( booleanarray )

Creates a boolean array from another boolean array.

var arr1 = new BooleanArray( [ true, false, false, true ] );
// returns <BooleanArray>

var arr2 = new BooleanArray( arr1 );
// returns <BooleanArray>

var len = arr2.length;
// returns 4

BooleanArray( typedarray )

Creates a boolean array from a typed array.

var Uint8Array = require( '@stdlib/array/uint8' );

var buf = new Uint8Array( [ 1, 0, 0, 1 ] );
// returns <Uint8Array>[ 1, 0, 0, 1 ]

var arr = new BooleanArray( buf );
// returns <BooleanArray>

var len = arr.length;
// returns 4

BooleanArray( obj )

Creates a boolean array from an array-like object or iterable.

// From an array of booleans:
var arr1 = new BooleanArray( [ true, false, false, true ] );
// returns <BooleanArray>

var len = arr1.length;
// returns 4

// From an array containing non-booleans:
var arr2 = new BooleanArray( [ {}, null, '', 4 ] );

len = arr2.length;
// returns 4

BooleanArray( buffer[, byteOffset[, length]] )

Returns a boolean array view of an ArrayBuffer.

var ArrayBuffer = require( '@stdlib/array/buffer' );
var buf = new ArrayBuffer( 240 );

var arr1 = new BooleanArray( buf );
// returns <BooleanArray>

var len = arr1.length;
// returns 240

var arr2 = new BooleanArray( buf, 8 );
// returns <BooleanArray>

len = arr2.length;
// returns 232

var arr3 = new BooleanArray( buf, 8, 20 );
// returns <BooleanArray>

len = arr3.length;
// returns 20

---

Properties

BooleanArray.BYTES_PER_ELEMENT

Static property returning the size (in bytes) of each array element.

var nbytes = BooleanArray.BYTES_PER_ELEMENT;
// returns 1

BooleanArray.name

Static property returning the constructor name.

var str = BooleanArray.name;
// returns 'BooleanArray'

BooleanArray.prototype.buffer

Pointer to the underlying data buffer.

var arr = new BooleanArray( 2 );
// returns <BooleanArray>

var buf = arr.buffer;
// returns <ArrayBuffer>

BooleanArray.prototype.byteLength

Size (in bytes) of the array.

var arr = new BooleanArray( 10 );
// returns <BooleanArray>

var nbytes = arr.byteLength;
// returns 10

BooleanArray.prototype.byteOffset

Offset (in bytes) of the array from the start of its underlying ArrayBuffer.

var ArrayBuffer = require( '@stdlib/array/buffer' );

var arr = new BooleanArray( 10 );
// returns <BooleanArray>

var offset = arr.byteOffset;
// returns 0

var buf = new ArrayBuffer( 240 );
arr = new BooleanArray( buf, 64 );
// returns <BooleanArray>

offset = arr.byteOffset;
// returns 64

BooleanArray.prototype.BYTES_PER_ELEMENT

Size (in bytes) of each array element.

var arr = new BooleanArray( 10 );
// returns <BooleanArray>

var nbytes = arr.BYTES_PER_ELEMENT;
// returns 1

BooleanArray.prototype.length

Number of array elements.

var arr = new BooleanArray( 10 );
// returns <BooleanArray>

var len = arr.length;
// returns 10

---

Methods

BooleanArray.from( src[, clbk[, thisArg]] )

Creates a new boolean array from an array-like object or an iterable.

var arr = BooleanArray.from( [ true, false ] );
// returns <BooleanArray>

var len = arr.length;
// returns 2

To invoke a function for each src value, provide a callback function.

function map( v ) {
    return !v;
}

// Create a source array:
var src = [ true, false ];

// Create a new boolean array by inverting the source array:
var arr = BooleanArray.from( src, map );
// returns <BooleanArray>

var len = arr.length;
// returns 2

var v = arr.get( 0 );
// returns false

v = arr.get( 1 );
// returns true

A callback function is provided two arguments:

• value: source value.
• index: source index.

To set the callback execution context, provide a thisArg.

function map( v ) {
    this.count += 1;
    return !v;
}

// Create a source array:
var src = [ true, false ];

// Define an execution context:
var ctx = {
    'count': 0
};

// Create a new boolean array by inverting the source array:
var arr = BooleanArray.from( src, map, ctx );
// returns <BooleanArray>

var len = arr.length;
// returns 2

var n = ctx.count;
// returns 2

BooleanArray.of( element0[, element1[, ...elementN]] )

Creates a new boolean array from a variable number of arguments.

var arr = BooleanArray.of( true, false, false, true );
// returns <BooleanArray>

var len = arr.length;
// returns 4

BooleanArray.prototype.find( predicate[, thisArg] )

Returns the first element in an array for which a predicate function returns a truthy value.

function predicate( v ) {
    return v === true;
}

var arr = new BooleanArray( 3 );

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var v = arr.find( predicate );
// returns true

The predicate function is provided three arguments:

• value: current array element.
• index: current array element index.
• arr: the array on which this method was called.

To set the function execution context, provide a thisArg.

function predicate( v ) {
    this.count += 1;
    return ( v === true );
}

var arr = new BooleanArray( 3 );

var context = {
    'count': 0
};

arr.set( false, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var z = arr.find( predicate, context );
// returns true

var count = context.count;
// returns 3

BooleanArray.prototype.findIndex( predicate[, thisArg] )

Returns the index of the first element in an array for which a predicate function returns a truthy value.

function predicate( v ) {
    return v === true;
}

var arr = new BooleanArray( 3 );

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var v = arr.findIndex( predicate );
// returns 0

The predicate function is provided three arguments:

• value: current array element.
• index: current array element index.
• arr: the array on which this method was called.

To set the function execution context, provide a thisArg.

function predicate( v ) {
    this.count += 1;
    return ( v === true );
}

var arr = new BooleanArray( 3 );

var context = {
    'count': 0
};

arr.set( false, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var z = arr.findIndex( predicate, context );
// returns 2

var count = context.count;
// returns 3

Complex64Array.prototype.findLast( predicate[, thisArg] )

Returns the last element in an array for which a predicate function returns a truthy value.

function predicate( v ) {
    return v === true;
}

var arr = new BooleanArray( 3 );

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var v = arr.findLast( predicate );
// returns true

The predicate function is provided three arguments:

• value: current array element.
• index: current array element index.
• arr: the array on which this method was called.

To set the function execution context, provide a thisArg.

function predicate( v ) {
    this.count += 1;
    return ( v === true );
}

var arr = new BooleanArray( 3 );

var context = {
    'count': 0
};

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( false, 2 );

var z = arr.findLast( predicate, context );
// returns true

var count = context.count;
// returns 3

BooleanArray.prototype.findLastIndex( predicate[, thisArg] )

Returns the index of the last element in an array for which a predicate function returns a truthy value.

function predicate( v ) {
    return v === true;
}

var arr = new BooleanArray( 3 );

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var v = arr.findLastIndex( predicate );
// returns 2

The predicate function is provided three arguments:

• value: current array element.
• index: current array element index.
• arr: the array on which this method was called.

To set the function execution context, provide a thisArg.

function predicate( v ) {
    this.count += 1;
    return ( v === true );
}

var arr = new BooleanArray( 3 );

var context = {
    'count': 0
};

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( false, 2 );

var z = arr.findLastIndex( predicate, context );
// returns 0

var count = context.count;
// returns 3

BooleanArray.prototype.get( i )

Returns an array element located at a nonnegative integer position (index) i.

var arr = new BooleanArray( 10 );

// Set the first element:
arr.set( true, 0 );

// Get the first element:
var v = arr.get( 0 );
// returns true

If provided an out-of-bounds index, the method returns undefined.

var arr = new BooleanArray( 10 );

var v = arr.get( 100 );
// returns undefined

BooleanArray.prototype.map( callbackFn[, thisArg] )

Returns a new array with each element being the result of a provided callback function.

function invert( v ) {
    return !v;
}

var arr = new BooleanArray( 3 );

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var out = arr.map( invert );
// returns <BooleanArray>

var z = out.get( 0 );
// returns false

z = out.get( 1 );
// returns true

z = out.get( 2 );
// returns false

The callback function is provided three arguments:

• value: current array element.
• index: current array element index.
• arr: the array on which this method was called.

To set the function execution context, provide a thisArg.

function invert( v, i ) {
    this.count += i;
    return !v;
}

var arr = new BooleanArray( 3 );

var context = {
    'count': 0
};

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

var out = arr.map( invert, context );
// returns <BooleanArray>

var count = context.count;
// returns 3;

BooleanArray.prototype.set( v[, i] )

Sets one or more array elements.

var arr = new BooleanArray( 10 );

// Get the first element:
var v = arr.get( 0 );
// returns false

// Set the first element:
arr.set( true );

// Get the first element:
v = arr.get( 0 );
// returns true

By default, the method sets array elements starting at position (index) i = 0. To set elements starting elsewhere in the array, provide an index argument i.

var arr = new BooleanArray( 10 );

// Get the fifth element:
var v = arr.get( 4 );
// returns false

// Set the fifth element:
arr.set( true, 4 );

// Get the fifth element:
v = arr.get( 4 );
// returns true

In addition to providing a single value, to set one or more array elements, provide an array-like object containing truthy and falsy values

var arr = new BooleanArray( 10 );

// Define an array of values:
var buf = [ '', 1, null ];

// Set the fifth, sixth, and seventh elements:
arr.set( buf, 4 );

// Get the sixth element:
var v = arr.get( 5 );
// returns true

A few notes:

• If i is out-of-bounds, the method throws an error.
• If a target array cannot accommodate all values (i.e., the length of source array plus i exceeds the target array length), the method throws an error.
• If provided a typed array which shares an ArrayBuffer with the target array, the method will intelligently copy the source range to the destination range.

BooleanArray.prototype.sort( [compareFcn] )

Sorts an array in-place.

function compare( a, b ) {
    if ( a === false ) {
        if ( b === false ) {
            return 0;
        }
        return 1;
    }
    if ( b === true ) {
        return 0;
    }
    return -1;
}

var arr = new BooleanArray( 3 );

arr.set( true, 0 );
arr.set( false, 1 );
arr.set( true, 2 );

arr.sort( compare );

var v = arr.get( 0 );
// returns true

v = arr.get( 1 );
// returns true

v = arr.get( 2 );
// returns false

The compareFcn determines the order of the elements. The function is called with the following arguments:

• a: the first boolean value for comparison.
• b: the second boolean value for comparison.

The function should return a number where:

• a negative value indicates that a should come before b.
• a positive value indicates that a should come after b.
• zero or NaN indicates that a and b are considered equal.

---

Notes

• While a BooleanArray strives to maintain (but does not guarantee) consistency with typed arrays, significant deviations from ECMAScript-defined typed array behavior are as follows:

  • The constructor does not require the new operator.
  • Accessing array elements using bracket syntax (e.g., X[i]) is not supported. Instead, one must use the .get() method.

---

Examples

var Uint8Array = require( '@stdlib/array/uint8' );
var logEach = require( '@stdlib/console/log-each' );
var BooleanArray = require( '@stdlib/array/bool' );

// Create a boolean array by specifying a length:
var out = new BooleanArray( 3 );
logEach( '%s', out );

// Create a boolean array from an array of booleans:
var arr = [ true, false, true ];
out = new BooleanArray( arr );
logEach( '%s', out );

// Create a boolean array from an array buffer:
arr = new Uint8Array( [ 1, 0, 1, 1, 0, 1 ] );
out = new BooleanArray( arr.buffer );
logEach( '%s', out );

// Create a boolean array from an array buffer view:
arr = new Uint8Array( [ 1, 0, 1, 1, 0, 1 ] );
out = new BooleanArray( arr.buffer, 1, 2 );
logEach( '%s', out );

console.log( '%s', false );