binary-insert/dist/index.js

Simple function `binaryInsert(array, value, comparator)` that provides binary insert functionality for a **sorted** array in javascript. This is mostly intended for larger arrays, and the performance gain may be viewed in the [benchmark](#benchmarks).

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.binaryInsert = void 0;
/**
 * Takes in a __SORTED__ array and inserts the provided value into
 * the correct, sorted, position.
 * @param array the sorted array where the provided value needs to be inserted (in order)
 * @param insertValue value to be added to the array
 * @param comparator function that helps determine where to insert the value (
 */
function binaryInsert(array, insertValue, comparator) {
    /*
    * These two conditional statements are not required, but will avoid the
    * while loop below, potentially speeding up the insert by a decent amount.
    * */
    if (array.length === 0 || comparator(array[0], insertValue) >= 0) {
        array.splice(0, 0, insertValue);
        return array;
    }
    else if (array.length > 0 && comparator(array[array.length - 1], insertValue) <= 0) {
        array.splice(array.length, 0, insertValue);
        return array;
    }
    var left = 0, right = array.length;
    var leftLast = 0, rightLast = right;
    while (left < right) {
        var inPos = Math.floor((right + left) / 2);
        var compared = comparator(array[inPos], insertValue);
        if (compared < 0) {
            left = inPos;
        }
        else if (compared > 0) {
            right = inPos;
        }
        else {
            right = inPos;
            left = inPos;
        }
        // nothing has changed, must have found limits. insert between.
        if (leftLast === left && rightLast === right) {
            break;
        }
        leftLast = left;
        rightLast = right;
    }
    // use right, because Math.floor is used
    array.splice(right, 0, insertValue);
    return array;
}
exports.binaryInsert = binaryInsert;