Javascript 对 Object.entries 的 Babel 支持
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Babel support for Object.entries
提问by damd
I'm looking at the stage 3 proposal of Object.values/Object.entriesand I'd really like to use it in my current JavaScript project.
我正在查看Object.values/Object.entries的第 3 阶段提案，我真的很想在我当前的 JavaScript 项目中使用它。
However, I can't figure out whether there's any Babel preset which supports it. Since the GitHub repository linked above says it's a stage 3 proposal, I assumed it would be part of babel-preset-stage-3, but it seems not.
但是，我不知道是否有任何支持它的 Babel 预设。由于上面链接的 GitHub 存储库说这是第 3 阶段的提案，我认为它是 babel-preset-stage-3 的一部分，但似乎不是。
Is there any Babel preset (or even plugin?) that lets me use Object.entries today?
是否有任何 Babel 预设（甚至插件？）可以让我今天使用 Object.entries？
回答by petersv
Using babel, installing
使用babel，安装
gives support for Object.values/Object.entriesas well as other *ES20** functionality.
支持Object.values/Object.entries以及其他 *ES20** 功能。
As per recommendation by the modules, configure .babelrcwith the following:
根据模块的建议，使用以下内容配置.babelrc：
{
"plugins": ["transform-runtime"],
"presets": ["env"]
}
回答by damd
What I did was install core-jsand then just call this at the top of my file:
我所做的是安装core-js，然后在我的文件顶部调用它：
require('core-js/fn/object/entries');
This made Object.entriesavailable. Credits to @FelixKling.
这使得Object.entries可用。归功于@FelixKling。
Update
更新
In core-js@3, the import path has changed:
在 core-js@3 中，导入路径发生了变化：
require('core-js/features/object/entries');
回答by Randy
Update:
更新：
As noted in the comments, you can improve performance by using the mapfunction instead of reduce.
如评论中所述，您可以通过使用map函数而不是来提高性能reduce。
Please note that the code is case-sensitive (object != Object).
请注意，代码区分大小写 ( object != Object)。
// Object.values
var objectToValuesPolyfill = function(object) {
return Object
.keys(object)
.map(
function(key) {
return object[key];
}
);
}
Object.values = Object.values || objectToValuesPolyfill;
// Object.entries
var objectToEntriesPolyfill = function(object) {
return Object
.keys(object)
.map(
function(key) {
return [key, object[key]];
}
);
}
Object.entries = Object.entries || objectToEntriesPolyfill;
Usage:
用法：
// es6
Object.values = Object.values || (x => Object.keys(x).map(k => x[k]));
Object.entries = Object.entries || (x => Object.keys(x).map(k => [k, x[k]]));
// es5
Object.values = Object.values || function(x){
return Object.keys(x).map(function(k){
return x[k];
})
};
Object.entries = Object.values || function(x){
return Object.keys(x).map(function(k){
return [k, x[k]];
})
};
const a = {
key: "value",
bool: true,
num: 123
}
console.log(
Object.values(a)
)
console.log(
Object.entries(a)
)