const minimum = 1const maximum = 1000var arr = Array.from({ length: 1000000 }, () => Math.floor(Math.random() * (maximum - minimum + 1)) + minimum)return arr.map((el) => Number(el))return arr.map((el) => parseInt(el))return arr.map((el) => el >> 0)return arr.map((el) => el * 1)return arr.map((el) => ~~el)return arr.map((el) => +el)--enable-precise-memory-info flag.
| Test case name | Result |
|---|---|
| Number | |
| parseInt | |
| >>0 | |
| *1 | |
| ~~ | |
| + |
| Test name | Executions per second |
|---|---|
| Number | 51.2 Ops/sec |
| parseInt | 63.6 Ops/sec |
| >>0 | 63.9 Ops/sec |
| *1 | 62.6 Ops/sec |
| ~~ | 64.2 Ops/sec |
| + | 64.4 Ops/sec |
Overview
MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark compares the ways to convert strings to numbers in JavaScript.
Benchmark Definition
The benchmark definition json provides a basic structure for the test, which includes:
Name: The name of the benchmark.Description: A brief description of the benchmark.Script Preparation Code: The code that prepares the data used in the benchmark. In this case, it generates an array of 1 million random integers between 1 and 1000.Html Preparation Code: Not used in this benchmark.Individual Test Cases
The individual test cases are defined by multiple json objects, each representing a different way to convert strings to numbers:
Number(): Uses the built-in Number() function to convert strings to numbers.parseInt(): Uses the parseInt() function to convert strings to numbers. Note that this will truncate any decimal part of the number.>> 0 (bit shift): Uses the bit shift operator (>>) to convert a string to an integer by shifting the bits to the right and then casting it back to an integer.*1: Multiplies the string by 1, effectively converting it to a number. This works because in JavaScript, multiplying any value by 0 returns 0, so multiplying by 1 has no effect.~~ (integer sign): Uses the bitwise NOT operator (~) and then takes the absolute value of the result with Math.abs(). However, since this does not cover all edge cases (like -0), it is considered slower than parseInt.+: Concatenates two strings together and then converts the resulting string to a number using the unary plus operator (+). This is a very slow way to convert strings to numbers.Library Usage
None of these test cases use any libraries.
Special JS Features/Syntax
The following special JavaScript features/syntax are used in some of the test cases:
>> 0: A bit shift operator that can be confusing to those not familiar with bitwise operations.~~: The integer sign operator, which is a less common feature and may not be supported by all browsers or environments.Pros and Cons
Here's a summary of the pros and cons for each approach:
Number(), parseInt(), and + are built-in functions that provide fast and reliable conversions. They have no significant downsides.>> 0: This is a clever way to convert strings to integers, but it relies on bitwise operations, which may be slower than the others. It also assumes that the string can be converted directly to an integer without fractional part.*1 is a quick fix, but it doesn't work well for negative numbers or strings containing decimal parts.~~: While this might seem like a good idea, it's not reliable and will fail with certain edge cases. It's generally slower than the other methods.Other Alternatives
Some alternative methods to convert strings to numbers could be used, such as:
json or number-expr that provides functions for parsing and converting strings to numbers.python's int().However, these alternatives are likely to be slower and less portable than the methods tested in this benchmark.
