Довідка помилок JavaScript

Нижче – список помилок, які викидаються JavaScript. Ці помилки можуть бути корисними при зневадженні, але виведена проблема не завжди є зразу зрозумілою. Сторінки нижче надають додаткові подробиці про ці помилки. Кожна помилка є об'єктом, заснованим на об'єкті Error, і має name і message.

Помилки, виведені у вебконсолі, можуть містити посилання на відповідну сторінку нижче, щоб допомогти швидко зрозуміти проблему у коді.

Вступний підручник початківця з усунення помилок JavaScript дивіться Що пішло не так? Зневадження JavaScript.

Список помилок

У цьому списку кожна сторінка перелічена за назвою (типом помилки) та повідомленням (більш докладним повідомленням про помилку, доступним для прочитання людиною). Разом ці дві властивості надають початкову точку для розуміння та вирішення помилки. Більше інформації – за посиланнями нижче!

• SyntaxError: arguments is not valid in fields
• TypeError: already executing generator
• Warning: -file- is being assigned a //# sourceMappingURL, but already has one
• SyntaxError: await/yield expression can\'t be used in parameter
• TypeError: invalid Array.prototype.sort argument
• SyntaxError: unlabeled break must be inside loop or switch
• SyntaxError: await is only valid in async functions, async generators and modules
• SyntaxError: new keyword cannot be used with an optional chain
• RangeError: radix must be an integer
• SyntaxError: continue must be inside loop
• SyntaxError: invalid regular expression flag "x"
• SyntaxError: tagged template cannot be used with optional chain
• SyntaxError: return not in function
• SyntaxError: super() is only valid in derived class constructors
• SyntaxError: \'arguments\'/\'eval\' can\'t be defined or assigned to in strict mode code
• SyntaxError: use of super property/member accesses only valid within methods or eval code within methods
• RangeError: BigInt division by zero
• RangeError: BigInt negative exponent
• TypeError: BigInt value can\'t be serialized in JSON
• TypeError: calling a builtin X constructor without new is forbidden
• TypeError: X.prototype.y called on incompatible type
• ReferenceError: can\'t access lexical declaration \'X\' before initialization
• RangeError: x can\'t be converted to BigInt because it isn\'t an integer
• TypeError: can\'t convert BigInt to number
• TypeError: can\'t convert x to BigInt
• TypeError: can\'t define property "x": "obj" is not extensible
• TypeError: can\'t assign to property "x" on "y": not an object
• TypeError: property "x" is non-configurable and can\'t be deleted
• SyntaxError: private fields can\'t be deleted
• TypeError: can\'t redefine non-configurable property "x"
• SyntaxError: cannot use ?? unparenthesized within || and && expressions
• TypeError: class constructors must be invoked with \'new\'
• TypeError: can\'t set prototype of this object
• TypeError: Iterator/AsyncIterator constructor can\'t be used directly
• TypeError: can\'t set prototype: it would cause a prototype chain cycle
• TypeError: cyclic object value
• TypeError: \'caller\', \'callee\', and \'arguments\' properties may not be accessed
• SyntaxError: "0"-prefixed octal literals are deprecated
• SyntaxError: applying the \'delete\' operator to an unqualified name is deprecated
• SyntaxError: octal escape sequences can\'t be used in untagged template literals or in strict mode code
• SyntaxError: duplicate formal argument x
• SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
• SyntaxError: property name __proto__ appears more than once in object literal
• SyntaxError: getter and setter for private name #x should either be both static or non-static
• SyntaxError: functions cannot be labelled
• RangeError: form must be one of \'NFC\', \'NFD\', \'NFKC\', or \'NFKD\'
• TypeError: can\'t access/set private field or method: object is not the right class
• SyntaxError: getter functions must have no arguments
• SyntaxError: Unexpected \'#\' used outside of class body
• TypeError: setting getter-only property "x"
• SyntaxError: illegal character
• SyntaxError: identifier starts immediately after numeric literal
• TypeError: cannot use \'in\' operator to search for \'x\' in \'y\'
• SyntaxError: import declarations may only appear at top level of a module
• SyntaxError: invalid assignment left-hand side
• TypeError: invalid assignment to const "x"
• RangeError: invalid array length
• TypeError: derived class constructor returned invalid value x
• SyntaxError: invalid BigInt syntax
• SyntaxError: for-in loop head declarations may not have initializers
• SyntaxError: a declaration in the head of a for-of loop can\'t have an initializer
• RangeError: invalid date
• TypeError: invalid \'instanceof\' operand \'x\'
• TypeError: \'x\' is not iterable
• SyntaxError: JSON.parse: bad parsing
• SyntaxError: label not found
• TypeError: WeakSet key/WeakMap value \'x\' must be an object or an unregistered symbol
• URIError: malformed URI sequence
• SyntaxError: missing : after property id
• SyntaxError: missing ] after element list
• SyntaxError: missing } after function body
• SyntaxError: missing } after property list
• SyntaxError: missing = in const declaration
• SyntaxError: missing formal parameter
• SyntaxError: missing name after . operator
• SyntaxError: missing ) after argument list
• RangeError: repeat count must be non-negative
• SyntaxError: missing ) after condition
• TypeError: More arguments needed
• TypeError: null/undefined has no properties
• SyntaxError: missing variable name
• TypeError: "x" is not a non-null object
• TypeError: "x" is not a constructor
• TypeError: can\'t delete non-configurable array element
• TypeError: "x" is not a function
• RangeError: argument is not a valid code point
• SyntaxError: parameter after rest parameter
• RangeError: precision is out of range
• TypeError: Initializing an object twice is an error with private fields/methods
• TypeError: getting private setter-only property
• AggregateError: No Promise in Promise.any was resolved
• TypeError: "x" is read-only
• Error: Permission denied to access property "x"
• SyntaxError: redeclaration of formal parameter "x"
• TypeError: Reduce of empty array with no initial value
• SyntaxError: duplicate capture group name in regular expression
• SyntaxError: \ at end of pattern
• SyntaxError: invalid capture group name in regular expression
• SyntaxError: invalid decimal escape in regular expression
• SyntaxError: character class escape cannot be used in class range in regular expression
• SyntaxError: incomplete quantifier in regular expression
• SyntaxError: invalid character in class in regular expression
• SyntaxError: invalid class set operation in regular expression
• SyntaxError: invalid identity escape in regular expression
• SyntaxError: invalid regexp group
• SyntaxError: invalid named capture reference in regular expression
• SyntaxError: invalid property name in regular expression
• SyntaxError: invalid range in character class
• SyntaxError: invalid unicode escape in regular expression
• SyntaxError: negated character class with strings in regular expression
• SyntaxError: nothing to repeat
• SyntaxError: numbers out of order in {} quantifier.
• SyntaxError: raw bracket is not allowed in regular expression with unicode flag
• SyntaxError: "x" is a reserved identifier
• TypeError: matchAll/replaceAll must be called with a global RegExp
• SyntaxError: rest parameter may not have a default
• RangeError: repeat count must be less than infinity
• SyntaxError: setter functions must have one argument
• SyntaxError: "use strict" not allowed in function with non-simple parameters
• Warning: unreachable code after return statement
• SyntaxError: string literal contains an unescaped line break
• ReferenceError: super() called twice in derived class constructor
• ReferenceError: must call super constructor before using \'this\' in derived class constructor
• SyntaxError: reference to undeclared private field or method #x
• ReferenceError: assignment to undeclared variable "x"
• InternalError: too much recursion
• SyntaxError: Unexpected token
• TypeError: "x" is (not) "y"
• SyntaxError: function statement requires a name
• SyntaxError: unparenthesized unary expression can\'t appear on the left-hand side of \'**\'
• ReferenceError: "x" is not defined