Some commonly used JS utility functions I use regularly.

js_utility_functions.js

Array.prototype.getItemCount = function (val) {
	var count = 0, i = -1;
	while ((i = this.indexOf(val, i + 1)) != -1) {
		count++;
	}
	return count;
};

Array.prototype.sortObjectsWithSingleKeyByValue = function (isAscending) {
	return (isAscending) ? this.sort((a, b) => a[Object.keys(a)[0]] - b[Object.keys(b)[0]]) : this.sort((a, b) => b[Object.keys(b)[0]] - a[Object.keys(a)[0]]);
};

Array.prototype.sortObjectsWithSingleKeyByKey = function (isAscending) {
	return (isAscending) ? this.sort((a, b) => Object.keys(a)[0] > Object.keys(b)[0]) : this.sort((a, b) => Object.keys(b)[0] > Object.keys(a)[0]);
};

Array.prototype.unique = function () {
	return this.filter((v, i) => ( this.indexOf(v) == i ));
};

Array.prototype.getFrequencyObjectArray = function () {
	var x = [];
	var arr = this;
	arr.unique().forEach(function (v, i) {
		var y = {};
		y.name = v;
		y.y = arr.getItemCount(v);
		x.push(y);
	});
	return x;
};

Array.prototype.getFrequencyObject = function () {
	var x = {};
	var arr = this;
	arr.unique().forEach(function (v, i) {
		x[v] = arr.getItemCount(v);
	});
	return x;
};

function objectsWithSingleKeyToObjectArrayA(obj) {
	return Object.keys(obj).map((v, i) => {
		var x = {};
		x[v] = obj[v];
		return x;
	});
}

function executeAsynchronously(functions, timeout) {
	for (var i = 0; i < functions.length; i++) {
		setTimeout(functions[i], timeout * i);
	}
}

//Function might have some mistakes
function parseCSV(data,hasHeaders) {
	data = data.split("\n").map(function (d) {
		return d.split(",");
	});
	if(data[data.length - 1] == ""){
		data.pop();
	}
	
	if(hasHeaders){
		var headers = data.splice(0, 1)[0];
		data = data.map(function (v, i) {
			var x = {};
			headers.forEach(function (h, i) {
				x[h] = v[i];
			});
			return x;
		});
	}

	//Do stuff with `data` and/or `headers`
}