[1,2,3].map(function(elem,index,arr){returnelem*index;});// [0, 2, 6] 此外,map()循环还可以接受第二个参数,用来绑定回调函数内部的this变量,将回调函数内部的this对象,指向第二个参数,间接操作这个参数(一般是数组)。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 vararr=['a','b','c...
numbers.map(function(n) {returnn +1; });// [2, 3, 4]numbers// [1, 2, 3] map方法接受一个函数作为参数。该函数调用时,map方法向它传入三个参数:当前成员、当前位置和数组本身。 [1,2,3].map(function(elem, index, arr) {returnelem * index; });// [0, 2, 6] 此外,map()循环还可...
ECMAScript中关于Array.prototype.sort(comparefn)的标准,其中并没有规定具体的实现算法,但是提到一点: Calling comparefn(a,b) always returns the same value v when given a specific pair of values a and b as its two arguments.也就是说,对同一组a、b的值,comparefn(a, b)需要总是返回相同的值。而上...
{ /* 也可以使用es7中的values方法 return object.values(this.items) */ // 在这里我们通过循环生成一个数组并输出 return object.keys( this .items).reduce((r, c, i) => { r.push( this .items[c]); return r; }, []); } } const dictionar...
You can minify more than one JavaScript file at a time by using an object for the first argument where the keys are file names and the values are source code: var code = { "file1.js": "function add(first, second) { return first + second; }", "file2.js": "console.log(add(1 ...
Promise.allSettled([p1, p2, p3, p4, p5]).then(values => { console.log(values); }, reason => {console.log(reason) }); // [ // {status:'fulfilled', value:'one'}, // {status:'fulfilled', value:'two'}, // {status:'fulfilled', value:'three'}, ...
Note that in the default configuration, without setting runScripts, the values of window.Array, window.eval, etc. will be the same as those provided by the outer Node.js environment. That is, window.eval === eval will hold, so window.eval will not run scripts in a useful way. We str...
function funTwo(){ // 内部函数 num++; return num; } return funTwo; } var fun = funOne(); // 返回函数 funTwo //以上代码就构成了一个闭包,其实就是函数 fun。 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
permissions by setting their permission value to 2147483647. That user could then have access to any route. As another example, a user whose permission value was set to 7 would have permissions to the roles marked with bits for values 1, 2, and 4 (two to the power of 0, 1, and 2)...
wx.config({ debug: true, // Enable the debug mode, and the returned values of all APIs that are called will be output as alerts in the app. You can view the incoming parameters on your PC and print the parameter information in a log on PC only. appId: '', // (Required) The uni...