Example of JavaScript method to calculate the actual length of string

Calculate the actual length of the string

Double-byte character (including Chinese characters) length meter 2, ASCII character meter 1

Method 1: Use match

export function getByteLenMatch(data) {
  let result = 0;
  for (let s of data) {
    result += (/[^\\x00-\\xff]/ig) == null ? 1 : 2;
  }
  return result;
}

Method 2: Use replace

export function getByteLenReplace(data) {
  return (/[^\\x00-\\xff]/ig, "aa").length;
}

Test code:

let testData = new Array(50000000).fill("ha").toString();
    for (let i = 0; i &lt; 3; i++) {
      ("getByteLenMatch");
      getByteLenMatch(testData);
      ("getByteLenMatch");
      ("getByteLenReplace");
      getByteLenReplace(testData);
      ("getByteLenReplace");
    }

Performance comparison (units ms)

String length	match	replace
50,000,000	8051	8626
50,000,000	9351	8019
50,000,000	10384	7512
10,000,000	1631	1783
10,000,000	1646	1343
10,000,000	1663	1372
5,000,000	799	728
5,000,000	822	806
5,000,000	884	645
1,000,000	165	128
1,000,000	166	143
1,000,000	170	113
500,000	84	58
500,000	83	54
500,000	86	61
100,000	20	7
100,000	18	5
100,000	20	5
50,000	11.79	3.01
50,000	10.39	2.68
50,000	11.99	2.82
10,000	4.13	0.60
10,000	4.32	0.59
10,000	5.48	0.58
5,000	1.88	0.31
5,000	1.36	0.33
5,000	2.71	0.31
1,000	1.67	0.07
1,000	0.21	0.07
1,000	1.02	0.06
500	0.0840	0.0322
500	0.0820	0.0332
500	0.0840	0.0320
100	0.0229	0.0100
100	0.0432	0.0149
100	0.0471	0.0161

In the case of large data volume, the performance of replace will be inferior to match at the first time, and will be superior to match after multiple executions. In the case of small data volume, the performance of replace will be superior to match at the first time, and in the case of small data volume, the performance of replace will be superior to match at the first time, and in the case of small data volume, the performance of replace will be superior to match at the first time, and after the first time, the performance of replace will be superior to match at the first time, and after the first time, the performance of replace will be superior to match at the first time.

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