# EMS Node Application Components: Utility Methods

Utility methods that are intended for use in NodeJS applications developed by [Educational Media Solutions](https://educationalmediasolutions.com).

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](https://underscorejs.org))

## 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<number>
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<any>
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("test@test.co"); //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,}))$/