Performance of splice

[amk221]

Is there anything that can be done to improve the performance of .splice

this.data = tracked([/* 10000 items */]);
console.time('splice');
this.data.splice(0, 1);
console.timeEnd('splice');
// 10ms

vs.

this.data = [/* 10000 items */];
console.time('splice');
this.data.splice(0, 1);
console.timeEnd('splice');
// 0.002

[lifeart]

I think we could have a test to catch this kind of regressions:

const array1 = new Array(100000).fill(null);
const t1 = performance.now();
array1.splice(0, 1);
const t2 = performance.now();
const controlWindow = t2-t1;

const array2 = tracked(new Array(100000).fill(null));
const t3 = performance.now();
array2.splice(0, 1);
const t4 = performance.now();
const experimentWindow = t4-t3;

const deviation = 1.2; // 20%
assert.ok(experimentWindow < controlWindow*deviation)