javascript - 如何在nodejs中向项目添加项目(How to add items to array in nodejs)

Question

How do I iterate through an existing array and add the items to a new array.

(如何遍历现有阵列并将项添加到新阵列。)

var array = [];
forEach( calendars, function (item, index) {
    array[] = item.id
}, done );

function done(){
   console.log(array);
}

The above code would normally work in JS, not sure about the alternative in node js .

(上面的代码通常可以在JS中使用，不确定node js的替代方法。)

I tried .push and .splice but neither worked.

(我试过.push和.splice但都没有奏效。)

  ask by Ben Scarberry translate from so

Answer 1

Check out Javascript's Array API for details on the exact syntax for Array methods.

(查看Javascript的Array API ，了解有关Array方法的确切语法的详细信息。)

Modifying your code to use the correct syntax would be:

(修改代码以使用正确的语法将是：)

var array = [];
calendars.forEach(function(item) {
    array.push(item.id);
});

console.log(array);

You can also use the map() method to generate an Array filled with the results of calling the specified function on each element.

(您还可以使用map()方法生成一个Array，其中填充了在每个元素上调用指定函数的结果。)

Something like:

(就像是：)

var array = calendars.map(function(item) {
    return item.id;
});

console.log(array);

And, since ECMAScript 2015 has been released, you may start seeing examples using let or const instead of var and the => syntax for creating functions.

(而且，自ECMAScript 2015发布以来，您可能会开始使用let或const而不是var和=>语法来创建函数。)

The following is equivalent to the previous example (except it may not be supported in older node versions):

(以下内容与上一个示例等效（旧版节点版本可能不支持）：)

let array = calendars.map(item => item.id);
console.log(array);