27 lines
818 B
JavaScript
27 lines
818 B
JavaScript
|
'use strict';
|
||
|
|
// https://tc39.github.io/proposal-setmap-offrom/
|
||
|
|
var aFunction = require('../internals/a-function');
|
||
|
|
var bind = require('../internals/function-bind-context');
|
||
|
|
var iterate = require('../internals/iterate');
|
||
|
|
|
||
|
|
module.exports = function from(source /* , mapFn, thisArg */) {
|
||
|
|
var length = arguments.length;
|
||
|
|
var mapFn = length > 1 ? arguments[1] : undefined;
|
||
|
|
var mapping, A, n, boundFunction;
|
||
|
|
aFunction(this);
|
||
|
|
mapping = mapFn !== undefined;
|
||
|
|
if (mapping) aFunction(mapFn);
|
||
|
|
if (source == undefined) return new this();
|
||
|
|
A = [];
|
||
|
|
if (mapping) {
|
||
|
|
n = 0;
|
||
|
|
boundFunction = bind(mapFn, length > 2 ? arguments[2] : undefined, 2);
|
||
|
|
iterate(source, function (nextItem) {
|
||
|
|
A.push(boundFunction(nextItem, n++));
|
||
|
|
});
|
||
|
|
} else {
|
||
|
|
iterate(source, A.push, A);
|
||
|
|
}
|
||
|
|
return new this(A);
|
||
|
|
};
|