How can I use an AngularJS filter to format a number to have leading zeros?

Question

I checked the documentation. What I would like is for my numbers to have four digits and leading zeros.

22 to 0022
1  to 0001

Can someone

Answer 1

This is an Angular 1.x variant of the directive in TypeScript which would handle both integers and decimals. Everything is considered 'type safe' thanks to TS.

adminApp.filter("zeroPadNumber",
    () => (num: number, len: number): string => {
        if (isNaN(num) || isNaN(len)) {
            return `${num}`;
        }
        if (`${num}`.indexOf(".") > -1) {
            var parts = `${num}`.split(".");
            var outDec = parts[0]; // read the before decimal
            while (outDec.length < len) {
                outDec = `0${outDec}`;
            }
            return outDec + parts[1]; // reappend the after decimal
        } else {
            var outInt = `${num}`;
            while (outInt.length < len) {
                outInt = `0${outInt}`;
            }
            return outInt;
        }
    });