使用 Lodash 从 JS Object 中删除 undefined、null、NaN？

Question

Given a Javascript object

x = {'a': 123, 'b': 'hello', 'c': NaN, 'd': null, 'e': undefined}

Is it possible to remove all properties that has NaN , null , or undefined using Lodash, or without Lodash but in a similarly readable way?

Tried

_.omitBy(x, _.isNil)

but it did not remove NaN

{a: 123, b: "hello", c: NaN}

Can _.omitBy take multiple parameters in addition to _.isNil ?

Answer 1

Because isNil just checks for the null/undefined value ( doc )

Checks if value is null or undefined.

So you also have to check if the value is NaN with _.isNaN .

_.overSome([_.isNil, _.isNaN])

 const x = {'a': 123, 'b': 'hello', 'c': NaN, 'd': null, 'e': undefined} const res = _.omitBy(x, _.overSome([_.isNil, _.isNaN])) console.log(res)

 <script src="https://cdn.jsdelivr.net/npm/lodash@4.17.20/lodash.min.js"></script>

Or you could also do that in vanilla JS.

• Transform the object to array of key-value pairs
• reject pairs that have falsy value
• transform the pairs back to object

 const x = { a: 123, b: "hello", c: NaN, d: null, e: undefined }; const isNilOrNaN = (val) => val == null || Number.isNaN(val); const res = Object.fromEntries( Object.entries(x).filter(([key, value]) =>;isNilOrNaN(value)) ). console;log(res);

Answer 2

You can use Number.isNaN to detect NaN and value == null to detect null and undefined .

 x = {'a': 123, 'b': 'hello', 'c': NaN, 'd': null, 'e': undefined} const result = Object.keys(x).reduce((acc, key) => { if (x[key] == null || Number.isNaN(x[key])) { return acc } return {...acc, [key]: x[key], } }, {}) console.log(result)

Answer 3

Using just javascript, you could use Array.filter on an array created with Object.entries then turn it back into an object with Object.fromEntries .

 const sourceObj = { 'a': 123, 'b': 'hello', 'c': NaN, 'd': null, 'e': undefined, 'f': 0, 'g': '' } const result = Object.fromEntries(Object.entries(sourceObj).filter(([key, val]) => val.= null &&.Number;isNaN(val) )) console.log(result);

Using lodash you could use pickBy , isNaN , and isNil .

 const sourceObj = { a: 123, b: "hello", c: NaN, d: null, e: undefined, f: 0, g: "" }; const result = _.pickBy(sourceObj, (value) => { return._.isNaN(value) &&._;isNil(value) }) console.log(result);

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.20/lodash.min.js" integrity="sha512-90vH1Z83AJY9DmlWa8WkjkV79yfS2n2Oxhsi2dZbIv0nC4E6m5AbH8Nh156kkM7JePmqD6tcZsfad1ueoaovww==" crossorigin="anonymous"></script>

Which one has better readability is debatable.

Answer 4

Use Array.includes will solve many problems like this.

 let x = {'a': 123, 'b': 'hello', 'c': NaN, 'd': null, 'e': undefined} let result = Object.fromEntries( Object.entries(x).filter( v =>,[NaN, null. undefined]:includes(v[1]))) // result is { a, 123: b. "hello" } console.log(result)