Essential Books

Check if string contains pattern using .test

suggest change 
var re = /[a-z]+/;
if (re.test("foo")) {
    console.log("Match exists.");
}

The test method performs a search to see if a regular expression matches a string. The regular expression [a-z]+ will search for one or more lowercase letters. Since the pattern matches the string, “match exists” will be logged to the console.

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Regular Expression:
* Syntax
* Parameters
* Creating a RegExp Object
* RegExp Flags
* Check if string contains pattern using .test
* Matching With .exec
* Using RegExp With Strings
* RegExp Groups
* Replacing string match with a callback function
* Using Regex.exec with parentheses regex to extract matches of a string
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0 Getting started
1 Comments
2 Basic data types
3 Built-in constants
4 Variables
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55 Async functions, async / await
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58 Performance Tips
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81 Automatic Semicolon Insertion
82 IndexedDB
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84 Navigator Object
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88 postMessage and MessageEvent
89 WeakMap
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91 Behaviroal Design Patterns
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94 Namespacing
95 Evaluating JavaScript
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97 How to make iterator usable inside async callback function
98 Context this
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100 Vibration API
101 Fluent API
102 Tilde
103 Security issues
104 Get and set CSS custom variables
105 Contributors