我试图使用动态名称访问对象的属性。这可能吗?
const something = { bar: "Foobar!" };
const foo = 'bar';
something.foo; // The idea is to access something.bar, getting "Foobar!"
我试图使用动态名称访问对象的属性。这可能吗?
const something = { bar: "Foobar!" };
const foo = 'bar';
something.foo; // The idea is to access something.bar, getting "Foobar!"
当前回答
你可以在Javascript中使用getter
getter文档
检查对象内部是否存在有问题的属性, 如果它不存在,就从窗口拿走
const something = {
get: (n) => this.n || something.n || window[n]
};
其他回答
演示对象示例
let obj = {
name: {
first_name: "Bugs",
last_name: "Founder",
role: "Programmer"
}
}
的值的虚线字符串键
let key = "name.first_name"
函数
const getValueByDottedKeys = (obj, strKey)=>{
let keys = strKey.split(".")
let value = obj[keys[0]];
for(let i=1;i<keys.length;i++){
value = value[keys[i]]
}
return value
}
调用getValueByDottedKeys函数
value = getValueByDottedKeys(obj, key)
console.log(value)
输出
Bugs
const getValueByDottedKeys = (obj, strKey)=>{ 让键= strKey.split(".") Let value = obj[keys[0]]; (让我= 1,< keys.length;我+ +){ Value = Value [key [i]] } 返回值 } 让obj = { 名称:{ first_name:“虫子”, last_name:“创始人”, 作用:“程序员” } } Let key = "name.first_name" value = getValueByDottedKeys(obj, key) console.log(值)
这是我的解决方案:
function resolve(path, obj) {
return path.split('.').reduce(function(prev, curr) {
return prev ? prev[curr] : null
}, obj || self)
}
使用例子:
resolve("document.body.style.width")
// or
resolve("style.width", document.body)
// or even use array indexes
// (someObject has been defined in the question)
resolve("part.0.size", someObject)
// returns null when intermediate properties are not defined:
resolve('properties.that.do.not.exist', {hello:'world'})
你可以在Javascript中使用getter
getter文档
检查对象内部是否存在有问题的属性, 如果它不存在,就从窗口拿走
const something = {
get: (n) => this.n || something.n || window[n]
};
对于任何想要设置嵌套变量值的人来说,下面是如何做的:
const _ = require('lodash'); //import lodash module
var object = { 'a': [{ 'b': { 'c': 3 } }] };
_.set(object, 'a[0].b.c', 4);
console.log(object.a[0].b.c);
// => 4
文档:https://lodash.com/docs/4.17.15
另外,如果您想获得一个值,可以查看文档:https://lodash.com/docs/4.17.15#get
通过引用查找对象,字符串, 注意,确保你传递的对象是克隆的,我使用cloneDeep从lodash
如果对象看起来像
const obj = {data: ['an Object',{person: {name: {first:'nick', last:'gray'} }]
路径看起来像这样
const objectPath = ['data',1,'person',name','last']
然后调用下面的方法,它将按给定的路径返回子对象
const child = findObjectByPath(obj, objectPath)
alert( child) // alerts "last"
const findObjectByPath = (objectIn: any, path: any[]) => {
let obj = objectIn
for (let i = 0; i <= path.length - 1; i++) {
const item = path[i]
// keep going up to the next parent
obj = obj[item] // this is by reference
}
return obj
}