add Belt.Array.joinWith

rescript implementation of Js Array.prototype.join()

Signed-Off-By: Paul Tsnobiladzé <paul.tsnobiladze@gmail.com>

Author: tsnobip

jscomp/main/builtin_cmi_datasets.ml

@@ -511,3 +511,14 @@ let unzip a =
     a2.!(i) <- v2
   done;
   (a1, a2)
+
+let joinWithU a sep toString =
+  match length a with
+  | 0 -> ""
+  | l ->
+      let lastIndex = l - 1 in
+      let rec aux i res =
+        if i = lastIndex then res ^ toString a.!(i) [@bs]
+        else aux (i + 1) (res ^ toString a.!(i) [@bs] ^ sep) in
+      aux 0 ""
+let joinWith a sep toString = joinWithU a sep (fun [@bs] x -> toString x)

jscomp/main/builtin_cmj_datasets.ml

@@ -524,6 +524,22 @@ val reduceWithIndex:  'a array -> 'b -> ('b -> 'a -> int -> 'b) -> 'b
     ]}
 *)
 
+val joinWithU: 'a array -> string -> ('a -> string [@bs]) -> string
+val joinWith: 'a array -> string -> ('a -> string) -> string
+(** [joinWith xs sep toString]
+    
+    Concatenates all the elements of [xs] converted to string with [toString], each separated by [sep], the string 
+    given as the second argument, into a single string.
+    If the array has only one element, then that element will be returned 
+    without using the separator.
+    If the array is empty, the empty string will be returned.
+    @example{[
+      joinWith [|0; 1|] ", " string_of_int = "0, 1"
+      joinWith [||] " " string_of_int = ""
+      joinWith [|1|] " " string_of_int = "1"
+    ]}
+*)
+
 val someU: 'a array -> ('a -> bool [@bs]) -> bool
 val some: 'a array -> ('a -> bool) -> bool
 (** [some xs p]

jscomp/others/belt_Array.ml

@@ -652,6 +652,30 @@ function unzip(a) {
         ];
 }
 
+function joinWithU(a, sep, toString) {
+  var l = a.length;
+  if (l === 0) {
+    return "";
+  }
+  var lastIndex = l - 1 | 0;
+  var _i = 0;
+  var _res = "";
+  while(true) {
+    var res = _res;
+    var i = _i;
+    if (i === lastIndex) {
+      return res + toString(a[i]);
+    }
+    _res = res + (toString(a[i]) + sep);
+    _i = i + 1 | 0;
+    continue ;
+  };
+}
+
+function joinWith(a, sep, toString) {
+  return joinWithU(a, sep, Curry.__1(toString));
+}
+
 export {
   get ,
   getExn ,
@@ -707,6 +731,8 @@ export {
   reduceReverse2 ,
   reduceWithIndexU ,
   reduceWithIndex ,
+  joinWithU ,
+  joinWith ,
   someU ,
   some ,
   everyU ,

jscomp/others/belt_Array.mli

@@ -652,6 +652,30 @@ function unzip(a) {
         ];
 }
 
+function joinWithU(a, sep, toString) {
+  var l = a.length;
+  if (l === 0) {
+    return "";
+  }
+  var lastIndex = l - 1 | 0;
+  var _i = 0;
+  var _res = "";
+  while(true) {
+    var res = _res;
+    var i = _i;
+    if (i === lastIndex) {
+      return res + toString(a[i]);
+    }
+    _res = res + (toString(a[i]) + sep);
+    _i = i + 1 | 0;
+    continue ;
+  };
+}
+
+function joinWith(a, sep, toString) {
+  return joinWithU(a, sep, Curry.__1(toString));
+}
+
 exports.get = get;
 exports.getExn = getExn;
 exports.set = set;
@@ -706,6 +730,8 @@ exports.reduceReverse2U = reduceReverse2U;
 exports.reduceReverse2 = reduceReverse2;
 exports.reduceWithIndexU = reduceWithIndexU;
 exports.reduceWithIndex = reduceWithIndex;
+exports.joinWithU = joinWithU;
+exports.joinWith = joinWith;
 exports.someU = someU;
 exports.some = some;
 exports.everyU = everyU;