The startsWith()
method of String
values determines whether this string begins with the characters of a specified string, returning true
or false
as appropriate.
The startsWith()
method of String
values determines whether this string begins with the characters of a specified string, returning true
or false
as appropriate.
startsWith(searchString) startsWith(searchString, position)
searchString
The characters to be searched for at the start of this string. Cannot be a regex. All values that are not regexes are coerced to strings, so omitting it or passing undefined
causes startsWith()
to search for the string "undefined"
, which is rarely what you want.
position
Optional
The start position at which searchString
is expected to be found (the index of searchString
's first character). Defaults to 0
.
true
if the given characters are found at the beginning of the string, including when searchString
is an empty string; otherwise, false
.
TypeError
Thrown if searchString
is a regex.
This method lets you determine whether or not a string begins with another string. This method is case-sensitive.
const str = "To be, or not to be, that is the question."; console.log(str.startsWith("To be")); // true console.log(str.startsWith("not to be")); // false console.log(str.startsWith("not to be", 10)); // true
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startsWith |
41 | 12 | 17 | 28 | 9 | 36 | 17 | 24 | 9 | 3.0 | 37 | 1.0 | 4.0.0 |
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith