如何在nodejs中向项目添加项目 [英] How to add items to array in nodejs
问题描述
如何遍历现有数组并将项添加到新数组中。
How do I iterate through an existing array and add the items to a new array.
var array = [];
forEach( calendars, function (item, index) {
array[] = item.id
}, done );
function done(){
console.log(array);
}
以上代码通常可以在JS中使用,不确定 node js
。我尝试过 .push
和 .splice
,但都没有用。
The above code would normally work in JS, not sure about the alternative in node js
. I tried .push
and .splice
but neither worked.
推荐答案
查看 Javascript的Array API ,了解有关Array方法的确切语法的详细信息。修改代码以使用正确的语法将是:
Check out Javascript's Array API for details on the exact syntax for Array methods. Modifying your code to use the correct syntax would be:
var array = [];
calendars.forEach(function(item) {
array.push(item.id);
});
console.log(array);
您还可以使用 map()
生成一个数组的方法,该数组填充了在每个元素上调用指定函数的结果。类似于:
You can also use the map()
method to generate an Array filled with the results of calling the specified function on each element. Something like:
var array = calendars.map(function(item) {
return item.id;
});
console.log(array);
而且,自ECMAScript 2015发布以来,您可能会开始看到使用的示例让
或 const
而不是 var
和 =>
创建函数的语法。以下内容与上一个示例等效(旧版节点版本可能不支持):
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. The following is equivalent to the previous example (except it may not be supported in older node versions):
let array = calendars.map(item => item.id);
console.log(array);
这篇关于如何在nodejs中向项目添加项目的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!