var example = 'there is no spoon'
var result = example.slice(0,-1)
var result = example.substr(10)
var result = example.substring(0,example.length - 1)
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
slice | |
substr | |
substring |
Test name | Executions per second |
---|---|
slice | 188255312.0 Ops/sec |
substr | 204660880.0 Ops/sec |
substring | 183796784.0 Ops/sec |
This benchmark tests the performance of three different methods in JavaScript for extracting substrings from a string: slice()
, substr()
, and substring()
.
Let's break down each method and their options:
1. slice()
: This method extracts a portion of a string defined by two indices:
Start Index (Required): Where the substring should begin.
End Index (Optional): The index where the substring ends (exclusive). If omitted, it includes all characters from the start index to the end of the string.
In this benchmark, slice(0,-1)
extracts a substring starting at index 0 and ending at (but not including) the last character of the string "there is no spoon"
.
2. substr()
: This method also extracts a portion of a string:
Start Index (Required): Where the substring should begin.
Length (Required): The number of characters to extract from the start index.
In this benchmark, substr(10)
extracts a substring starting at index 10 and taking length
characters after that. This example doesn't specify the length, so it will include all characters after the 10th position in the string.
3. substring()
:
Start Index (Required): Where the substring should begin.
End Index (Optional): The index where the substring ends (exclusive). If omitted, it includes all characters from the start index to the end of the string.
In this benchmark, substring(0, example.length - 1)
extracts a substring starting at index 0 and ending at (but not including) the last character of the string. This is functionally similar to using slice(0,-1)
.
Pros/Cons and Considerations:
slice()
: Often considered the most versatile due to its ability to handle both start and end indices, providing precise control over extracted portions.
substr()
: Simpler for extracting a fixed length from a specific starting point. Less flexible than slice()
.
substring()
: Similar in functionality to slice()
but can sometimes have slight performance variations. Less common due to the presence of slice()
, which offers more flexibility.
Alternatives: While these methods are standard in JavaScript, there are often alternative ways to achieve similar results, depending on your specific needs:
RegExp
): Powerful for complex pattern matching and substring extraction, but can be less efficient for simple cases.indexOf
, lastIndexOf
): Can be combined to extract substrings by finding specific characters or patterns.Let me know if you have any other questions about this benchmark or JavaScript string manipulation techniques!