@seges/angular-validators/src/app/validators/value/integer.ts

TypeScript 1.8.10

import { IValidator } from "../IValidator";

export class IntegerValidator implements IValidator<void> {
    private regex: RegExp;

    constructor() {
        this.regex = new RegExp("^[0-9]*$");
    }

    /**
     * Validate input as integer.
     * If value is parseable to integer return true. Otherwise return false.
     */
    isValid(value: string | number): boolean {
        if (!value) {
            return false;
        }

        if (typeof value === "string") {
            return this.regex.test(value);
        }

        // Number.isInteger() polyfill implementation from MDN
        // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger#Polyfill
        if (typeof value === "number") {
            return isFinite(value)
                    && value > -9007199254740992
                    && value < 9007199254740992
                    && Math.floor(value) === value;
        }

        return false;
    }
}