Typescript - checking for null and undefined the easy way [duplicate]

Question

I'm working on an Angular 11 project and I'm struggling with checking for null and undefined.

I have three strings - equipmentId, roomId and personnelId and a flag (boolean) adresseeChosen.

I want the adresseeChosen to be true if at least one of the above strings is not null / undefined, this is my code

this.adresseeChosen= (this.equipmentId != null && this.equipmentId != undefined)  
                      || (this.roomId != null && this.roomId != undefined) 
                      || (this.personnelId != null && this.personnelId != undefined)

What's the short way of writing this? Thanks!

(this.equipmentId != null || this.roomId != null || this.personnelId != null) — VLAZ
– VLAZ, Commented Feb 20, 2021 at 9:02
Also relevant: Checking for null or undefined | How can I determine if a variable is 'undefined' or 'null'? | JavaScript checking for null vs. undefined and difference between == and === | What is the difference between null and undefined in JavaScript? — VLAZ
– VLAZ, Commented Feb 20, 2021 at 9:03
@VLAZ I got that, but I'm looking for a even shorter approach ;) — Vasile Verssachen
– Vasile Verssachen, Commented Feb 20, 2021 at 9:06
Write a function to do the check? There isn't really a "shorter" way to check if three things satisfy some condition other than testing each of the three things. I don't know what you expect us to give you. Any code that will mean "check if x, y, or z are not null" still has to name the three of them. Your other alternative is to minify your code to save out a few bytes. It's still going to use the same operations but might you'd get about 6 characters less. — VLAZ
– VLAZ, Commented Feb 20, 2021 at 9:11

Saghi Shiri · Accepted Answer · 2021-02-20 09:50:36Z

2

You can write an utility function to check value is null or undefined. For example:

export function isNullUndefined(value): boolean {
  return (value === null) || (value === undefined);
}

answered Feb 20, 2021 at 9:50

Saghi Shiri

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1 Comment

Maizied Hasan Majumder Over a year ago

This is a possible solution: stackoverflow.com/a/36125081/7921804

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