Make function wait until element exists

Question

I\'m trying to add a canvas over another canvas – how can I make this function wait to start until the first canvas is created?

function PaintObject(brush) {         


        

Answer 1

Just use setTimeOut with recursion:

waitUntilElementIsPresent(callback: () => void): void {
    if (!this.methodToCheckIfElementIsPresent()) {
        setTimeout(() => this.waitUntilElementIsPresent(callback), 500);
        return;
    }
    callback();
}

Usage:

this.waitUntilElementIsPresent(() => console.log('Element is present!'));

You can limit amount of attempts, so an error will be thrown when the element is not present after the limit:

waitUntilElementIsPresent(callback: () => void, attempt: number = 0): void {
    const maxAttempts = 10;
    if (!this.methodToCheckIfElementIsPresent()) {
        attempt++;
        setTimeout(() => this.waitUntilElementIsPresent(callback, attempt), 500);
        return;
    } else if (attempt >= maxAttempts) {
        return;
    }
    callback();
}