I want to know whether my array contains any undefined value. My array is like this,

How to find it? I tried this method but it doesn't read 'undefined'

 let newValues = []
 if(values.length === selectedCertifiedList.length){
   values && values.filter(v => v === (undefined ||  0 || null)).map(val => {
        newValues.push(val);
   })
 }

I want to know whether my array contains any undefined value. My array is like this,

How to find it? I tried this method but it doesn't read 'undefined'

 let newValues = []
 if(values.length === selectedCertifiedList.length){
   values && values.filter(v => v === (undefined ||  0 || null)).map(val => {
        newValues.push(val);
   })
 }

• javascript

• 1 What are your exact requirements? Do you want value or index? – Ankit Kumar Gupta Commented Feb 20, 2020 at 8:49
• @ankitgupta, say correct what you want exactly, values or check contain undefined values available or not? – R.G.Krish Commented Feb 20, 2020 at 8:55
• @Leya Have you got output or not? – R.G.Krish Commented Feb 20, 2020 at 9:06
• I want to check if the array contains any undefined value, if it contains I want to stop a function. – Lex V Commented Feb 20, 2020 at 9:17
• arr.some(x=> x===undefined) – Deee Commented Feb 20, 2020 at 9:27

3 Answers 3

arr.some(item => item === undefined)

returns true if any item in the array is undefined

let arr = ['a', undefined, 'b']
arr.indexOf(undefined) !== -1  //true

It will return true if undefined present in the array.

Try this,

const data = ['one', 0, 'two',  undefined, 'three'];
const checker = [null, undefined, 0]; //filtering conditions
const x = data.filter((item) => !checker.includes(item) )
console.log(data)
console.log(x)

//Output looks ["one","two","three"]