vue hello world项目
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'use strict';
// https://tc39.github.io/proposal-setmap-offrom/
var bind = require('../internals/function-bind-context');
var call = require('../internals/function-call');
var aCallable = require('../internals/a-callable');
var aConstructor = require('../internals/a-constructor');
var iterate = require('../internals/iterate');
var push = [].push;
module.exports = function from(source /* , mapFn, thisArg */) {
var length = arguments.length;
var mapFn = length > 1 ? arguments[1] : undefined;
var mapping, array, n, boundFunction;
aConstructor(this);
mapping = mapFn !== undefined;
if (mapping) aCallable(mapFn);
if (source == undefined) return new this();
array = [];
if (mapping) {
n = 0;
boundFunction = bind(mapFn, length > 2 ? arguments[2] : undefined);
iterate(source, function (nextItem) {
call(push, array, boundFunction(nextItem, n++));
});
} else {
iterate(source, push, { that: array });
}
return new this(array);
};