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String extension
Some popular methods added to the String object in ES6 are −
| Sr.No | Method & Description |
|---|---|
| 1 |
str.startsWith(searchString[, position]) determines whether a string begins with the characters of a specified string. Returns true or false
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| 2 |
str.endsWith(searchString[, length]) determines whether a string ends with the characters of a specified string. Returns true/false
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| 3 |
str.includes(searchString[, position]) determines whether one string may be found within another string
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| 4 |
str.repeat(count) constructs and returns a new string which contains the specified number of copies of the string on which it was called, concatenated together
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Regex extensions
In a regular expression, for example, /[A-Z]/g, the beginning and ending / are called delimiters. Anything after the closing delimiter is called a modifier. ES6 adds a new modifier /g where g stands for global. This match all instances of the pattern in a string, not just one.
Example
The following example searches and returns all upper-case characters in the string.
<script> let str = ''JJavascript is Fun to Work , very Fun '' let regex = /[A-Z]/g // g stands for global matches let result = str.match(regex); console.log(result) </script>
The output of the above code will be as given below −
["J", "J", "F", "W", "F"]
Regular expression searches are case-sensitive. To turn-off case-sensitivity, use the /i modifier.
Example
The following example performs a case insensitive global match. The example replaces fun with enjoyable.
<script> // /gi global match ignore case let str = ''Javascript is fun to Work , very Fun '' let regex = /Fun/gi; console.log(str.replace(regex,''enjoyable'')); console.log(str) console.log(str.search(regex)) </script>
The output of the above code will be as shown below −
Javascript is enjoyable to Work , very enjoyable Javascript is fun to Work , very Fun 15
Number
Some popular methods added to the Number object in ES6 are −
| Sr.No | Method & Description |
|---|---|
| 1 |
Number.isFinite(value) method determines whether the passed value is a finite number. Returns true/false.
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| 2 |
Number.isNaN(value) returns true if the given value is NaN and its type is Number; otherwise, false.
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| 3 |
Number.parseFloat(string) A floating-point number parsed from the given value. If the value cannot be converted to a number, NaN is returned.
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| 4 |
Number.parseInt(string,[ radix]) method parses a string argument and returns an integer of the specified radix or base.
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Math
Some popular methods added to the Math object in ES6 are −
| Sr.No | Method & Description |
|---|---|
| 1 |
Math.sign() function returns the sign of a number, indicating whether the number is positive, negative or zero.
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| 2 |
Math.trunc() function returns the integer part of a number by removing any fractional digits.
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Methods of Array in ES6
The table given below highlights the different array methods in ES6 along with the description.
| Sr.No | Method & Description |
|---|---|
| 1 |
copyWithin() shallow copies part of an array to another location in the same array and returns it without modifying its length.
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| 2 |
entries() method returns a new Array Iterator object that contains the key/value pairs for each index in the array.
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| 3 |
find() method returns the value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned..
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| 4 |
fill() method fills all the elements of an array from a start index to an end index with a static value. It returns the modified array.
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| 5 |
Array.of() method creates a new Array instance from a variable number of arguments, regardless of number or type of the arguments.
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| 6 |
Array.from() method creates a shallow copy from an array like or iterable object.
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Object
Methods related to Object function are mentioned below in the table along with the respective description.
| Sr.No | Method & Description |
|---|---|
| 1 |
Object.is() method determines whether two values are the same value
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| 2 |
Object.setPrototypeOf() method sets the prototype of a specified object to another object or null.
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| 3 |
Object.assign() method is used to copy the values of all enumerable own properties from one or more source objects to a target object. It will return the target object.
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