EMS Node Application Components: Utility Methods

Utility methods that are intended for use in NodeJS applications developed by Educational Media Solutions.

These utility methods act like globally scoped functions (though they're not really).

Note that there is a peer dependency defined for this library that must also be installed (underscore.js)

Usage

npm i underscore ems-node-app-utils --save

Module Usage:

import { trace, delay } from "ems-node-app-utils";

Methods

alphabetize(...parameters: any[]): any

Can be used as the callback argument to Array.sort

(["e","a","c", "d", "b"]).sort(alphabetize); // ["a", "b", "c", "d", "e"]

Also can be used to alphabetize array of objects using key (note: this method mutates original array)

alphabetize([{"label": "b"}, { "label": "a" }], "label"); //[{ "label": "a" }, {"label": "b"}]

clone(obj: any): any

Creates a deep copy of the supplied object. References are not maintained. Recursion not supported.

const copy = clone({hello: [{ nested: "object", params: [1,2,3] }]}); //{hello: [{ nested: "object", params: [1,2,3] }]}

dateStrings(date?: Date): { year: string, month: string, date: string, time: string seconds: string }

Returns a hash of date properties as strings (for formatting)

const dateinfo = dateStrings(new Date("2021/01/01")); { year: "2021", "month": "01", "date": "01", "time": "00:00", "seconds": "00" }

delay(method: () => void, ms: number = 0): number

Alias for setTimeout

delay(() => console.log("test")); // same as setTimeout(() => console.log("test"), 0);
delay(() => console.log("test"),100); // same as setTimeout(() => console.log("test"), 100);

empty(e: any): boolean

alias for falsy

enumKeys<O extends object, K extends keyof O = keyof O>(obj: O): K[]

Returns an array of keys in an enum typescript object

enum Grade {
  K = "K",
  Grade1 = "1",
  Grade2 = "2",
  Grade3 = "3",
  Grade4 = "4",
  Grade5 = "5"
}

const keys = enumKeys(Grade); // ["K", "Grade1", "Grade2", "Grade3", "Grade4", "Grade5"];

enumValues<O extends object, K extends keyof O = keyof O>(obj: O): any[]

Returns an array of values in an enum typescript object

enum Grade {
  K = "K",
  Grade1 = "1",
  Grade2 = "2",
  Grade3 = "3",
  Grade4 = "4",
  Grade5 = "5"
}

const values = enumValues(Grade); // ["K", "1", "2", "3", "4", "5"];

falsy(e: any): boolean

Evaluates whether supplied object is falsy or empty.

const obj = {}; falsy(obj); //true
const obj = {hello: "world"}; falsy(obj); //false
const arr = []; falsy(arr); //true
const arr = [1,2,3]; falsy(arr); //false
const str = ""; falsy(str); //true
const str = "   "; falsy(str); //true
const str = "hello"; falsy(str); //false
const bool = false; falsy(bool); //true
const bool = true; falsy(bool); //false
const boolString = "False"; falsy(boolString); //true
const boolString = "false"; falsy(boolString); //true
const boolString = "FalSe"; falsy(boolString); //true
const boolString = "true"; falsy(boolString); //false
const num = 0; falsy(num); //true
const num = -1; falsy(num); //false
const num = 1; falsy(num); //false

getLargestRemainder(values: number[], desiredSum: number): number[]

Handles rounding errors when calculating sub percentages of a data set. Ensures that all segments add up to 100%.

getLargestRemainder([24, 25, 50]); // [25,25,50]

isset(e: any): boolean

alias for truthy

kebab(e: string): string

Converts string to kebab case

kebab("Hello Big_World 2022-01-01"); // "hello-big-world-2022-01-01"

replaceItem(array: any[], item: any, key: string = 'id', position: string = 'current'): any

Swaps an item in an array with a newer value

const array = [ { id: 1, name: "Old Name" }, { id: 2, name: "Test User" }];
replaceItem(array, {id: 1, name: "New Name"}); // [ { id: 1, name: "New Name" }, { id: 2, name: "Test User" }]

const array2 = [ { id: 1, name: "Old Name" }, { id: 2, name: "Test User" }];
replaceItem(array, { id: 200, name: "Test User" }, "name"); // [ { id: 1, name: "Old Name" }, { id: 200, name: "Test User" }]

sleep(duration: number = 0):Promise

A combination of tick and delay called with an async function to pause the execution for the provided number of milliseconds.

async function doSomething() {
	$(".element-to-transition-out.render").removeClass("render");
	await sleep(250)
	$(".element-to-transition-out").hide();
	$(".element-to-transition-in").show();
	await sleep(0);
	$(".element-to-transition-in").addClass("render");
	await sleep(250);
	console.log("transition complete!");
}

snakecase(e: string): string

Converts string to snake case

snakecase("Hello Big-World 2022-01-01"); // "hello_big_world_2022_01_01"

tick(returnValue?: any): Promise

Awaits one turn of the JS engine

async function test() {
	$(".torender").css("display","block").addClass("transparent"); //renders the object on screen with 0 opactiy
	await tick(); // browser tick paints the above state
	$(".torender").removeClass("transparent); //animates opacity to 1 to fade in object
}

timestamp(date?: Date, includeTime: boolean = true): string

Returns MySQL date/time string from optionally supplied date

const date = new Date("2021/01/01"); 
const dateString = timestamp(date); // "2021-01-01 00:00:00";
const dateString2 = timestamp(date, false); // "2021-01-01";
const nowDateString = timestamp(); // whatever the current date time is

trace(...parameters: any[])

Outputs each argument to a line in console log IF ?debug=true parameter is set on the url (This method is an homage to the like-named, late great ActionScript 2 utility function)

trace(someObject, anotherObject, "---", 123); //four console logs at http://localhost/?debug=true

trim(e: string): string

Removes leading and trailing whitespace from string

trim("  hello   "); // "hello"

truthy(e:any): boolean

Evaluates whether supplied object is truthy or populated

const obj = {}; truthy(obj); //false
const obj = {hello: "world"}; truthy(obj); //true
const arr = []; truthy(arr); //false
const arr = [1,2,3]; truthy(arr); //true
const str = ""; truthy(str); //false
const str = "   "; truthy(str); //false
const str = "hello"; truthy(str); //true
const bool = false; truthy(bool); //false
const bool = true; truthy(bool); //true
const boolString = "False"; truthy(boolString); //false
const boolString = "false"; truthy(boolString); //false
const boolString = "FalSe"; truthy(boolString); //false
const boolString = "true"; truthy(boolString); //true
const num = 0; truthy(num); //false
const num = -1; truthy(num); //true
const num = 1; truthy(num); //true

validateEmail(email:string): boolean

Applies regex to test for valid email

validateEmail("test@test"); //false
validateEmail("[email protected]"); //true

Uses regex ex:

/^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/