I am absolute beginner on TypeScript. I want to initialize an array of numbers in TypeScript by "for" loop as you see in the following:
public hours: number[];
constructor() {
for (let i: number = 1; i < 25; i++) {
this.hours[i] = i;
}
}
I get an error: Cannot set property '1' of undefined. Could you please help me?
This line:
public hours: number[];
Does not create a new array, it only declares it.
If you compile this code:
class MyClass {
public hours: number[];
constructor() {
for (let i: number = 1; i < 25; i++) {
this.hours[i] = i;
}
}
}
You get:
var MyClass = (function () {
function MyClass() {
for (var i = 1; i < 25; i++) {
this.hours[i] = i;
}
}
return MyClass;
}());
As you can see, this.hours isn't being assigned.
So you need to do this:
constructor() {
this.hours = [];
for (let i: number = 1; i < 25; i++) {
this.hours[i] = i;
}
}
Or:
public hours: number[] = [];
hours isn't set to any value. You can create a new array in the constructor, or set hours to an empty array:
public hours: number[] = [];
constructor() {
for (let i: number = 1; i < 25; i++) {
this.hours[i] = i;
}
}
hours = new Array()