Programming-Idioms

History of Idiom 12 > diff from v66 to v67

Edit summary for version 67 by crdrost:
[JS] Because there is a more expressive way to do it

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Version 66

2019-09-26, 14:33:23

Version 67

2019-09-26, 14:43:09

Idiom #12 Check if list contains a value

Check if list contains a value x.
list is an iterable finite container.

Idiom #12 Check if list contains a value

Check if list contains a value x.
list is an iterable finite container.

Extra Keywords

array vector

Extra Keywords

array vector

Code

list.indexOf(x) !== -1

Code

list.includes(x) // newer
list.indexOf(x) !== -1 // older

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Array.prototype.includes() is preferred but if you are supporting browsers that are 5+ years old, for example IE 11 , and you are not using a transpiler, then the old syntax is generally well-understood.

Doc URL

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf

Doc URL

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf

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History of Idiom 12 > diff from v66 to v67

Version 66

Version 67

Idiom #12 Check if list contains a value

Idiom #12 Check if list contains a value

Extra Keywords

Extra Keywords

Code

Code

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Doc URL

Doc URL

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