TypeScript-optimization

Tests and benchmarks different codes in TypeScript for different JavaScript versions (ES5 vs ES6 and above).

Benchmarks are done inside Atom (using script package) and Webstorm.

Traditional for vs for-of vs for-in- Looping ovr Arrays

• ES6 and above: traditional for is faster than for-of that is faster than for-in
• ES5 and lower:Traditional for is similar to for-of and both faster than for-in.

// Traditional
  let sum = 0
  for (let i = 0, l = arr.length; i < l; ++i) {
    sum += arr[i]
  }

// for - of
  let sum = 0
  for (const a of arr) {
    sum += a
  }

// for - in
  let sum = 0
  for (const i in arr) {
    sum += arr[i]
  }

Benchmark-Result

ES2020:

for-traditional x 111,162 ops/sec ±0.16% (96 runs sampled)
for-of x 83,331 ops/sec ±0.15% (96 runs sampled)
for-in x 2,544 ops/sec ±0.86% (94 runs sampled)
Fastest is for-traditional

ES 6:

for-traditional x 110,622 ops/sec ±0.34% (95 runs sampled)
for-of x 83,102 ops/sec ±0.16% (94 runs sampled)
for-in x 2,521 ops/sec ±1.21% (94 runs sampled)
Fastest is for-traditional

ES5:

for-traditional x 110,584 ops/sec ±0.56% (95 runs sampled)
for-of x 110,395 ops/sec ±0.60% (98 runs sampled)
for-in x 2,604 ops/sec ±1.05% (95 runs sampled)
Fastest is for-traditional,for-of

Traditional for optimization

• in all versions: all the codes are about the same.

Defining arr as const or let doesn't affect the speed.

// for-traditional
  let sum = 0
  for (let i = 0, l = arr.length; i < l; ++i) {
    sum += arr[i]
  }
// for-traditional-const
  let sum = 0
  const l = arr.length
  for (let i = 0; i < l; ++i) {
    sum += arr[i]
  }

// for-traditional-length-lookup
  let sum = 0
  for (let i = 0; i < arr.length; ++i) {
    sum += arr[i]
  }

Benchmark-Result

const arr

ES2020:

for-traditional x 111,107 ops/sec ±0.38% (97 runs sampled)
for-traditional-const x 111,392 ops/sec ±0.19% (98 runs sampled)
for-traditional-lookup x 111,242 ops/sec ±0.22% (95 runs sampled)
Fastest is for-traditional,for-traditional-const,for-traditional-length-lookup

ES 6:

for-traditional x 111,197 ops/sec ±0.18% (95 runs sampled)
for-traditional-const x 111,209 ops/sec ±0.18% (96 runs sampled)
for-traditional-lookup x 111,111 ops/sec ±0.13% (96 runs sampled)
Fastest is for-traditional,for-traditional-const,for-traditional-length-lookup

ES5:

for-traditional x 111,351 ops/sec ±0.17% (98 runs sampled)
for-traditional-const x 111,326 ops/sec ±0.15% (96 runs sampled)
for-traditional-lookup x 110,693 ops/sec ±0.42% (97 runs sampled)
Fastest is for-traditional

let arr:

 ES2020:

for-traditional x 111,310 ops/sec ±0.23% (93 runs sampled)
for-traditional-const x 111,201 ops/sec ±0.36% (96 runs sampled)
for-traditional-lookup x 111,430 ops/sec ±0.20% (99 runs sampled)
Fastest is for-traditional-length-lookup,for-traditional,for-traditional-const

ES5:

for-traditional x 110,594 ops/sec ±0.53% (94 runs sampled)
for-traditional-const x 111,455 ops/sec ±0.14% (97 runs sampled)
for-traditional-lookup x 111,463 ops/sec ±0.15% (96 runs sampled)
Fastest is for-traditional-const,for-traditional-length-lookup