Typescript general utilities

.General TS Utilities.md

General TypeScript Utilities

Contains some helpful TypeScript functions.

general-utilities.ts

export class GeneralUtilities {
    /**
     * Retrieves the given function's argument names
     * @param func The function to retrieve the argument names from
     * @returns List of argument names
     */
    public static getFunctionArgumentNames(func: () => any): string[] {
        // Retrieve the function's signature (first line in a stringified function)
        const signature = func.toString().split('\n')[0];

        const args = signature
            .substring(signature.indexOf('(') + 1, signature.indexOf(')')) // Retrieve the args (between parantheses)
            .split(',') // Split on the argument separator ',' to separate the arguments
            .map((arg) => arg.trim()) // Trim any spaces surrounding arguments
            .filter((arg) => arg.length > 0); // Filter out any non-arguments, which are empty strings

        return args;
    }
    
    /**
     * Checks if the user agent is an Internet Explorer user agent
     */
    public static userAgentIsIE(): boolean {
        return navigator.userAgent.indexOf('MSIE') !== -1
            || navigator.appVersion.indexOf('Trident/') > 0
            || /Trident\//ig.test(navigator.userAgent);
    }
    
    /**
     * Distance between coordinates formula.
     * Formula used from SO answer => https://stackoverflow.com/a/5548877/4795677
     * The 111.2 value represents KM/degree of the earth,
     * see => https://www.thoughtco.com/degree-of-latitude-and-longitude-distance-4070616
     * The 57.3 value represents roughly 180/pi.
     * @param originLatitude The origin latitude.
     * @param originLongitude The origin longitude.
     * @param destinationLatitude The destination latitude.
     * @param destinationLongitude The destination longitude.
     */
    private calculateCoordinateDistance(
        originLatitude: number,
        originLongitude: number,
        destinationLatitude: number,
        destinationLongitude: number
    ): number {
        return Math.pow(
            111.2 * (originLongitude - destinationLongitude)
            * Math.cos(destinationLatitude / 57.3), 2
        ) + Math.pow(111.2 * (destinationLatitude - originLatitude), 2);
    }
}