How do i Check object.property is defined in angular 2?

Question

Is there any equivalent function in angular 2 as angular.isDefined as in angular 1

Checked The safe navigation operator ?. which only supports in tempalte

Answer 1

Typescript does NOT have a function to check if a variable is defined, neither does Angular2.

Using a juggling-check, you can test both null and undefined in one hit:

if (object.property == null) {

If you use a strict-check, it will only be true for values set to null and won't evaluate as true for undefined variables:

if (object.property === null) {

Answer 2

no

angular2 uses proper JavaScript. it moves away from angular specific language. that is one of its goals.

just do ..

if (something == null) { // the only exception where double equals is OK - checks for undefined or null
    ...
}

Typescript does have a !. operator which might be worth looking at, not exactly sure how it works but i think it is similar to ?.

Answer 3

you could use undefined

function getSchool(name: string, address?: string, pinCode?: string): string {
            if (address == undefined) {
                console.log('address not defined');
            }
            if (pinCode == undefined) {
                console.log('pincode not defined');
            }
}