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
• 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
• TypeError: invalid Array.prototype.sort argument
• SyntaxError: await is only valid in async functions, async generators and modules
• SyntaxError: unlabeled break must be inside loop or switch
• SyntaxError: continue must be inside loop
• SyntaxError: new keyword cannot be used with an optional chain
• SyntaxError: tagged template cannot be used with optional chain
• RangeError: radix must be an integer
• SyntaxError: invalid regular expression flag "x"
• SyntaxError: \'arguments\'/\'eval\' can\'t be defined or assigned to in strict mode code
• SyntaxError: return not in function
• SyntaxError: super() is only valid in derived class constructors
• 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 assign to property "x" on "y": not an object
• TypeError: can\'t convert BigInt to number
• TypeError: can\'t define property "x": "obj" is not extensible
• TypeError: can\'t convert x to BigInt
• 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
• SyntaxError: applying the \'delete\' operator to an unqualified name is deprecated
• TypeError: \'caller\', \'callee\', and \'arguments\' properties may not be accessed
• SyntaxError: "0"-prefixed octal literals are deprecated
• SyntaxError: octal escape sequences can\'t be used in untagged template literals or in strict mode code
• SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
• SyntaxError: property name __proto__ appears more than once in object literal
• RangeError: form must be one of \'NFC\', \'NFD\', \'NFKC\', or \'NFKD\'
• SyntaxError: getter and setter for private name #x should either be both static or non-static
• SyntaxError: duplicate formal argument x
• SyntaxError: functions cannot be labelled
• SyntaxError: getter functions must have no arguments
• TypeError: can\'t access/set private field or method: object is not the right class
• TypeError: setting getter-only property "x"
• SyntaxError: Unexpected \'#\' used outside of class body
• SyntaxError: illegal character
• SyntaxError: import declarations may only appear at top level of a module
• TypeError: cannot use \'in\' operator to search for \'x\' in \'y\'
• SyntaxError: identifier starts immediately after numeric literal
• SyntaxError: invalid assignment left-hand side
• RangeError: invalid array length
• SyntaxError: invalid BigInt syntax
• TypeError: invalid assignment to const "x"
• RangeError: invalid date
• 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
• TypeError: derived class constructor returned invalid value x
• TypeError: \'x\' is not iterable
• TypeError: invalid \'instanceof\' operand \'x\'
• SyntaxError: label not found
• SyntaxError: JSON.parse: bad parsing
• TypeError: WeakSet key/WeakMap value \'x\' must be an object or an unregistered symbol
• URIError: malformed URI sequence
• SyntaxError: missing ] after element list
• SyntaxError: missing : after property id
• SyntaxError: missing } after property list
• SyntaxError: missing } after function body
• SyntaxError: missing name after . operator
• SyntaxError: missing formal parameter
• SyntaxError: missing = in const declaration
• SyntaxError: missing ) after argument list
• RangeError: repeat count must be non-negative
• SyntaxError: missing ) after condition
• 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: null/undefined has no properties
• TypeError: "x" is not a function
• RangeError: argument is not a valid code point
• RangeError: precision is out of range
• SyntaxError: parameter after rest parameter
• TypeError: Initializing an object twice is an error with private fields/methods
• AggregateError: No Promise in Promise.any was resolved
• TypeError: getting private setter-only property
• Error: Permission denied to access property "x"
• SyntaxError: redeclaration of formal parameter "x"
• TypeError: "x" is read-only
• TypeError: Reduce of empty array with no initial value
• SyntaxError: \ at end of pattern
• SyntaxError: character class escape cannot be used in class range in regular expression
• SyntaxError: duplicate 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 capture group name in regular expression
• SyntaxError: invalid decimal escape in regular expression
• SyntaxError: invalid regexp group
• SyntaxError: invalid identity escape in regular expression
• SyntaxError: invalid named capture reference in regular expression
• SyntaxError: invalid property name in regular expression
• SyntaxError: invalid unicode escape in regular expression
• SyntaxError: numbers out of order in {} quantifier.
• SyntaxError: negated character class with strings in regular expression
• SyntaxError: invalid range in character class
• 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: rest parameter may not have a default
• RangeError: repeat count must be less than infinity
• SyntaxError: setter functions must have one argument
• SyntaxError: "x" is a reserved identifier
• SyntaxError: "use strict" not allowed in function with non-simple parameters
• Warning: unreachable code after return statement
• ReferenceError: must call super constructor before using \'this\' in derived class constructor
• SyntaxError: string literal contains an unescaped line break
• ReferenceError: super() called twice in derived class constructor
• InternalError: too much recursion
• SyntaxError: reference to undeclared private field or method #x
• ReferenceError: assignment to undeclared variable "x"
• 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