Declare an array in TypeScript

Question

I m having trouble either declaring or using a boolean array in Typescript  not sure which is wrong  I get an undefined error  Am I supposed to use JavaScript syntax or declare a new Array object    Which one of these is the correct way to create the array   private columns   boolean    private columns       private columns   new Array lt boolean gt       How would I initialize all the values to be false   How would I access the values  can I access them like  columns i    true

User · Accepted Answer

Here are the different ways in which you can create an array of booleans in typescript:

let arr1: boolean[] = [];
let arr2: boolean[] = new Array();
let arr3: boolean[] = Array();

let arr4: Array<boolean> = [];
let arr5: Array<boolean> = new Array();
let arr6: Array<boolean> = Array();

let arr7 = [] as boolean[];
let arr8 = new Array() as Array<boolean>;
let arr9 = Array() as boolean[];

let arr10 = <boolean[]> [];
let arr11 = <Array<boolean>> new Array();
let arr12 = <boolean[]> Array();

let arr13 = new Array<boolean>();
let arr14 = Array<boolean>();

You can access them using the index:

console.log(arr[5]);

and you add elements using push:

arr.push(true);

When creating the array you can supply the initial values:

let arr1: boolean[] = [true, false];
let arr2: boolean[] = new Array(true, false);

User · Answer

this is how you can create an array of boolean in TS and initialize it with false   var array  boolean      false  false  false    or another approach can be   var array2  Array lt boolean gt    false  false  false     you can specify the type after the colon which in this case is boolean array

User · Answer

Few ways of declaring a typed array in TypeScript are const booleans  Array lt boolean gt    new Array lt boolean gt        OR  JS like type and initialization const booleans  boolean             or  if you have values to initialize  const booleans  Array lt boolean gt     true  false  true      get a vaue from that array normally const valFalse   booleans 1

User · Answer

let arr1  boolean          console log arr1 1     arr1 push true

User · Answer

Specific type of array in typescript  export class RegisterFormComponent         genders   new Array lt GenderType gt          Use any array supports different kind objects       loadGenders                  this genders push  name   Male  isoCode  1            this genders push  name   FeMale  isoCode  2              type GenderType     name  string  isoCode  number          Specified format

[javascript] Declare an array in TypeScript

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