perf(runtime): improve getType() GC and speed

[jpsc]

While running some hot path optimisation within a Nuxt application (server-side) I found out that getType was creating unnecessary levels of GC.

This PR tries to optimize it by reducing the creation of temporary objects and strings which are the primary contributors to garbage collection (GC) activity. Functions like toString() and match() can create temporary strings and objects that may increase GC activity if called frequently.

I've validated that the amount of GC was reduced and speed improved.
This benchmark is worth what is worth but give's a rough idea.

Micro-benchmark

// Original getType function
function getTypeOriginal(ctor) {
  const match = ctor && ctor.toString().match(/^\s*(function|class) (\w+)/);
  return match ? match[2] : ctor === null ? "null" : "";
}

// Optimized getType function
function getTypeOptimized(ctor) {
  if (ctor === null) {
    return "null";
  }
  
  if (typeof ctor === 'function') {
    return ctor.name || '';
  } else if (typeof ctor === 'object') {
    const name = ctor.constructor && ctor.constructor.name;
    return name || '';
  }

  return '';
}

// Test inputs
const inputs = [
  function myFunc() {},
  class MyClass {},
  null,
  {},
  [],
  /regex/,
  'string',
  123,
  true,
  function() {}
];

// Benchmark original function
console.time('Original getType');
for (let i = 0; i < 10000; i++) {
  inputs.forEach(input => getTypeOriginal(input));
}
console.timeEnd('Original getType');

// Benchmark optimized function
console.time('Optimized getType');
for (let i = 0; i < 10000; i++) {
  inputs.forEach(input => getTypeOptimized(input));
}
console.timeEnd('Optimized getType');

Original getType: 13.35009765625 ms
Optimized getType: 2.468994140625 ms

[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	90.4 kB (+51 B)	34.4 kB (-8 B)	31 kB (-29 B)
vue.global.prod.js	148 kB (+51 B)	53.7 kB (-5 B)	47.9 kB (+61 B)

Usages

Name	Size	Gzip	Brotli
createApp	50.6 kB (+51 B)	19.7 kB (-10 B)	18 kB (-10 B)
createSSRApp	53.9 kB (+51 B)	21.1 kB (-8 B)	19.2 kB (-49 B)
defineCustomElement	52.8 kB (+51 B)	20.5 kB (-8 B)	18.7 kB (-4 B)
overall	64.3 kB (+51 B)	24.8 kB (-8 B)	22.5 kB (+4 B)

[index23]

@jpsc In which environment did you run this test? Did you consider to put test in pipeline?