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!

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