All: Use Lerna to manage monorepo

packages/lib/ArrayUtils.js

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+const ArrayUtils = {};
+
+ArrayUtils.unique = function(array) {
+	return array.filter(function(elem, index, self) {
+		return index === self.indexOf(elem);
+	});
+};
+
+ArrayUtils.removeElement = function(array, element) {
+	const index = array.indexOf(element);
+	if (index < 0) return array;
+	const newArray = array.slice();
+	newArray.splice(index, 1);
+	return newArray;
+};
+
+// https://stackoverflow.com/a/10264318/561309
+ArrayUtils.binarySearch = function(items, value) {
+	let startIndex = 0,
+		stopIndex = items.length - 1,
+		middle = Math.floor((stopIndex + startIndex) / 2);
+
+	while (items[middle] != value && startIndex < stopIndex) {
+		// adjust search area
+		if (value < items[middle]) {
+			stopIndex = middle - 1;
+		} else if (value > items[middle]) {
+			startIndex = middle + 1;
+		}
+
+		// recalculate middle
+		middle = Math.floor((stopIndex + startIndex) / 2);
+	}
+
+	// make sure it's the right value
+	return items[middle] != value ? -1 : middle;
+};
+
+ArrayUtils.findByKey = function(array, key, value) {
+	for (let i = 0; i < array.length; i++) {
+		const o = array[i];
+		if (typeof o !== 'object') continue;
+		if (o[key] === value) return o;
+	}
+	return null;
+};
+
+ArrayUtils.contentEquals = function(array1, array2) {
+	if (array1 === array2) return true;
+	if (!array1.length && !array2.length) return true;
+	if (array1.length !== array2.length) return false;
+
+	for (let i = 0; i < array1.length; i++) {
+		const a1 = array1[i];
+		if (array2.indexOf(a1) < 0) return false;
+	}
+
+	return true;
+};
+
+// Merges multiple overlapping intervals into a single interval
+// e.g. [0, 25], [20, 50], [75, 100] --> [0, 50], [75, 100]
+ArrayUtils.mergeOverlappingIntervals = function(intervals, limit) {
+	intervals.sort((a, b) => a[0] - b[0]);
+
+	const stack = [];
+	if (intervals.length) {
+		stack.push(intervals[0]);
+		for (let i = 1; i < intervals.length && stack.length < limit; i++) {
+			const top = stack[stack.length - 1];
+			if (top[1] < intervals[i][0]) {
+				stack.push(intervals[i]);
+			} else if (top[1] < intervals[i][1]) {
+				top[1] = intervals[i][1];
+				stack.pop();
+				stack.push(top);
+			}
+		}
+	}
+	return stack;
+};
+
+module.exports = ArrayUtils;