如何删除JavaScript对象中未定义或空的所有属性?
(这个问题与数组的问题类似)
如何删除JavaScript对象中未定义或空的所有属性?
(这个问题与数组的问题类似)
当前回答
ES6 arrow function and ternary operator:
Object.entries(obj).reduce((acc, entry) => {
const [key, value] = entry
if (value !== undefined) acc[key] = value;
return acc;
}, {})
const obj = {test:undefined, test1:1 ,test12:0, test123:false};
const newObj = Object.entries(obj).reduce((acc, entry) => {
const [key, value] = entry
if (value !== undefined) acc[key] = value;
return acc;
}, {})
console.log(newObj)
其他回答
如果你想要4行纯ES7解决方案:
const clean = e => e instanceof Object ? Object.entries(e).reduce((o, [k, v]) => {
if (typeof v === 'boolean' || v) o[k] = clean(v);
return o;
}, e instanceof Array ? [] : {}) : e;
或者如果你喜欢更易读的版本:
function filterEmpty(obj, [key, val]) {
if (typeof val === 'boolean' || val) {
obj[key] = clean(val)
};
return obj;
}
function clean(entry) {
if (entry instanceof Object) {
const type = entry instanceof Array ? [] : {};
const entries = Object.entries(entry);
return entries.reduce(filterEmpty, type);
}
return entry;
}
这将保留布尔值,也将清理数组。它还通过返回一个清理过的副本来保存原始对象。
清除空数组、空对象、空字符串、未定义、NaN和空值。
function objCleanUp(obj:any) {
for (var attrKey in obj) {
var attrValue = obj[attrKey];
if (attrValue === null || attrValue === undefined || attrValue === "" || attrValue !== attrValue) {
delete obj[attrKey];
} else if (Object.prototype.toString.call(attrValue) === "[object Object]") {
objCleanUp(attrValue);
if(Object.keys(attrValue).length===0)delete obj[attrKey];
} else if (Array.isArray(attrValue)) {
attrValue.forEach(function (v,index) {
objCleanUp(v);
if(Object.keys(v).length===0)attrValue.splice(index,1);
});
if(attrValue.length===0)delete obj[attrKey];
}
}
}
objCleanUp(myObject)
(attrValue !== attrValue)检查NaN。在这里学的
var testObject = { test1:“零”, test2:空, test3:“somestring”, test4: 3, test5:“定义”, test6:未定义的, } 函数removeObjectItem (obj) { For (var key in obj) { 如果(String (obj(例子))= = =“零”| |字符串(obj(例子))= = =“定义”){ 删除obj(例子); } } 返回obj } console.log (removeObjectItem (testObject))
下面是一个使用ES6从对象中删除null值的函数式方法,而不需要只使用reduce来改变对象:
const stripNulls = (obj) => {
return Object.keys(obj).reduce((acc, current) => {
if (obj[current] !== null) {
return { ...acc, [current]: obj[current] }
}
return acc
}, {})
}
如果你不想修改原始对象(使用一些ES6操作符):
const keys = Object.keys(objectWithNulls).filter(key => objectWithNulls[key]);
const pairs = keys.map(key => ({ [key]: objectWithNulls[key] }));
const objectWithoutNulls = pairs.reduce((val, acc) => ({ ...val, ...acc }));
过滤器(key => objectWithNulls[key])返回任何为真值的值,因此将拒绝任何值,如0或false,以及undefined或null。可以很容易地更改为过滤器(key => objectWithNulls[key] !== undefined)或类似的东西,如果这是不想要的行为。