JavaScript npm webpack live coding, 90min rant on modern JavaScript. 2019-10-31

topics talked:

• thanks to hello beautiful people, for this excellent and faster JavaScript array range function JS: Range Function for Array
• JS: Array.prototype.flat
• https://github.com/jonschlinkert/arr-flatten
• JS: Test Equality of Objects
• JS: Timing JavaScript Code

'use strict';

/* [
xah_is_array_equal(array1, array2)
Return true if 2 array are equal
Allow array-like object
Allow nested array

http://xahlee.info/js/js_comparison_equality_test_objects.html
version 2019-04-24
 ] */
const xah_is_array_equal = ((array1, array2) =>
{
    // allow array-like object
    if ( Array.isArray(array1) !== Array.isArray(array2) ) { return false; }
    if (array1.length !== array2.length) { return false; }

    return Array.prototype.every.call(
        array1,
        ((x, i) => {
            const y = array2[i];
            if ( Array.isArray(x) ) {
                if ( ! Array.isArray(y) ) {
                    return false;}
                else {
                    return xah_is_array_equal(x, y); }
            } else if ( typeof x === "object" && typeof x !== null) {
                if (! ( typeof y === "object" && typeof y !== null)) {
                    return false;}
                else {
                    return xah_is_obj_equal(x,y); }
            } else {
                return (x === y);
            }
        })
    );
});

function flat_jon(arr, res) {
  var i = 0, cur;
  var len = arr.length;
  for (; i < len; i++) {
    cur = arr[i];
    Array.isArray(cur) ? flat_jon(cur, res) : res.push(cur);
  }
  return res;
}

const flat_xah = ((array1, n) =>
{
    if ( n === undefined ) { n = 1; }
    if ( n > 0 &&
         Array.prototype.some.call(array1, Array.isArray )
       ) {
        return flat_xah(Array.prototype.concat.apply([],array1), n-1); }
    else {
        return array1; }
});

// -----------------------------------
// test

// const aa = [0,[1,[2,[3,[4,[5,[6]]]]]], "xyz"];

const aa = [[['a', ['b', ['k', ['a', ['b', ['c'], [['a', [['a', ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]], ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]], ['a', ['x', ['c'], ['a', ['x', ['k']], [['a', ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]];

console.log (
xah_is_array_equal( flat_jon(aa, []) ,  flat_xah(aa, 99))
);

{
// timing
const aa = [[['a', ['b', ['k', ['a', ['b', ['c'], [['a', [['a', ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]], ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]], ['a', ['x', ['c'], ['a', ['x', ['k']], [['a', ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]];
const test_repeat_count = 500;
const start = new Date().getTime();
for (let i = 0; i < test_repeat_count; ++i) { flat_jon(aa, []); }
const end = new Date().getTime();
// result
console.log( end - start);
}

{
// timing
const aa = [[['a', ['b', ['k', ['a', ['b', ['c'], [['a', [['a', ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]], ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]], ['a', ['x', ['c'], ['a', ['x', ['k']], [['a', ['b', ['k', ['a', ['b', ['c']], ['a', ['x', ['c'], ['a', ['x', ['k']]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]], ['d', ['z']]]], ['d', ['m']]], ['d', ['e']]]]], ['d', ['e']]]];
const test_repeat_count = 500;
const start = new Date().getTime();
for (let i = 0; i < test_repeat_count; ++i) { flat_xah(aa, 999); }
const end = new Date().getTime();
// result
console.log( end - start);
}

// console.log ( flat_jon(aa, []) );
// console.log ( flat_xah(aa, 99) );

// console.log( aa );
// console.log( flat_xah(aa) );
// console.log( flat_xah(aa,1) );
// console.log( flat_xah(aa,2) );
// console.log( flat_xah(aa,3) );
// console.log( flat_xah(aa,4) );
// console.log( flat_xah(aa,400) );

xah_talk_show_2019-10-31.txt