| Category |
Function |
Description |
| Core JavaScript Functions |
eval(string) |
Evaluates JavaScript code represented as a string. |
| parseInt(string, radix) |
Converts a string to an integer, optionally specifying the base (radix). |
| parseFloat(string) |
Converts a string to a floating-point number. |
| isNaN(value) |
Determines whether a value is NaN (Not-a-Number). |
| isFinite(value) |
Determines whether a value is a finite number. |
| encodeURI(uri) |
Encodes a Uniform Resource Identifier (URI) by escaping certain characters. |
| decodeURI(uri) |
Decodes a URI encoded by encodeURI. |
| encodeURIComponent(uriComponent) |
Encodes a URI component by escaping characters. |
| decodeURIComponent(uriComponent) |
Decodes a URI component encoded by encodeURIComponent. |
| escape(string) (Deprecated) |
Encodes a string for use in URLs. |
| unescape(string) (Deprecated) |
Decodes a string encoded by escape. |
| Math Functions |
Math.abs(x) |
Returns the absolute value of a number. |
| Math.ceil(x) |
Rounds a number upward to the nearest integer. |
| Math.floor(x) |
Rounds a number downward to the nearest integer. |
| Math.round(x) |
Rounds a number to the nearest integer. |
| Math.random() |
Returns a pseudo-random number between 0 (inclusive) and 1 (exclusive). |
| Math.max(...values) |
Returns the largest of zero or more numbers. |
| Math.min(...values) |
Returns the smallest of zero or more numbers. |
| Math.pow(base, exponent) |
Returns the base raised to the power of the exponent. |
| Math.sqrt(x) |
Returns the square root of a number. |
| Math.trunc(x) |
Returns the integer part of a number by removing the fractional part. |
| String Methods |
String.fromCharCode(...codes) |
Converts Unicode values to a string. |
| str.charAt(index) |
Returns the character at the specified index in a string. |
| str.charCodeAt(index) |
Returns the Unicode of the character at the specified index. |
| str.concat(...strings) |
Combines two or more strings. |
| str.includes(substring) |
Checks if a string contains a substring. |
| str.indexOf(substring) |
Returns the position of the first occurrence of a specified value. |
| str.lastIndexOf(substring) |
Returns the position of the last occurrence of a specified value. |
| str.split(separator) |
Splits a string into an array of substrings. |
| str.slice(start, end) |
Extracts a section of a string. |
| str.toUpperCase() |
Converts a string to uppercase. |
| str.toLowerCase() |
Converts a string to lowercase. |
| str.trim() |
Removes whitespace from both ends of a string. |
| str.replace(searchValue, newValue) |
Replaces specified values in a string. |
| str.substring(start, end) |
Extracts characters between two indices in a string. |
| Array Methods |
Array.isArray(value) |
Checks if a value is an array. |
| arr.push(...items) |
Adds one or more elements to the end of an array. |
| arr.pop() |
Removes and returns the last element of an array. |
| arr.shift() |
Removes and returns the first element of an array. |
| arr.unshift(...items) |
Adds one or more elements to the beginning of an array. |
| arr.slice(start, end) |
Returns a shallow copy of a portion of an array. |
| arr.splice(start, deleteCount, ...items) |
Adds or removes elements from an array. |
| arr.concat(...arrays) |
Merges two or more arrays. |
| arr.indexOf(value) |
Returns the first index of a specified value. |
| arr.lastIndexOf(value) |
Returns the last index of a specified value. |
| arr.forEach(callback) |
Executes a function for each array element. |
| arr.map(callback) |
Creates a new array with results from a function. |
| arr.filter(callback) |
Returns a new array with elements that pass a test. |
| arr.reduce(callback, initialValue) |
Reduces an array to a single value. |
| arr.find(callback) |
Returns the first element that satisfies a test. |
| arr.findIndex(callback) |
Returns the index of the first element that satisfies a test. |
| arr.includes(value) |
Checks if an array includes a value. |
| arr.join(separator) |
Joins array elements into a string. |
| arr.sort(compareFunction) |
Sorts the elements of an array. |
| arr.reverse() |
Reverses the order of an array. |
| Date Methods |
Date.now() |
Returns the current timestamp in milliseconds. |
| new Date() |
Creates a new Date object. |
| date.getFullYear() |
Returns the year of a date. |
| date.getMonth() |
Returns the month (0-11) of a date. |
| date.getDate() |
Returns the day of the month. |
| date.getDay() |
Returns the day of the week (0-6). |
| date.getHours() |
Returns the hour of a date. |
| date.getMinutes() |
Returns the minutes of a date. |
| date.getSeconds() |
Returns the seconds of a date. |
| date.toISOString() |
Converts a date to an ISO string. |