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RangeError: form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD' - JavaScript | MDN
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RangeError: form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD'

The JavaScript exception "form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD'" occurs when an unrecognized string is passed to the String.prototype.normalize() method.

In this article

Message

RangeError: The normalization form should be one of NFC, NFD, NFKC, NFKD. (V8-based) RangeError: form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD' (Firefox) RangeError: argument does not match any normalization form (Safari)

Error type

RangeError

What went wrong?

The String.prototype.normalize() method only accepts the following four values as its form argument: "NFC", "NFD", "NFKC", or "NFKD". If you pass any other value, an error will be thrown. Read the reference of normalize() to learn about different normalization forms.

Examples

Invalid cases

js
"foo".normalize("nfc"); // RangeError "foo".normalize(" NFC "); // RangeError

Valid cases

js
"foo".normalize("NFC"); // 'foo'

See also

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  1. JavaScript
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  13. Errors
    1. AggregateError: No Promise in Promise.any was resolved
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    3. InternalError: too much recursion
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    5. RangeError: BigInt division by zero
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    7. RangeError: form must be one of 'NFC', 'NFD', 'NFKC', or 'NFKD'
    8. RangeError: invalid array length
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    43. SyntaxError: incomplete quantifier in regular expression
    44. SyntaxError: invalid assignment left-hand side
    45. SyntaxError: invalid BigInt syntax
    46. SyntaxError: invalid capture group name in regular expression
    47. SyntaxError: invalid character in class in regular expression
    48. SyntaxError: invalid class set operation in regular expression
    49. SyntaxError: invalid decimal escape in regular expression
    50. SyntaxError: invalid identity escape in regular expression
    51. SyntaxError: invalid named capture reference in regular expression
    52. SyntaxError: invalid property name in regular expression
    53. SyntaxError: invalid range in character class
    54. SyntaxError: invalid regexp group
    55. SyntaxError: invalid regular expression flag "x"
    56. SyntaxError: invalid unicode escape in regular expression
    57. SyntaxError: JSON.parse: bad parsing
    58. SyntaxError: label not found
    59. SyntaxError: missing : after property id
    60. SyntaxError: missing ) after argument list
    61. SyntaxError: missing ) after condition
    62. SyntaxError: missing ] after element list
    63. SyntaxError: missing } after function body
    64. SyntaxError: missing } after property list
    65. SyntaxError: missing = in const declaration
    66. SyntaxError: missing formal parameter
    67. SyntaxError: missing name after . operator
    68. SyntaxError: missing variable name
    69. SyntaxError: negated character class with strings in regular expression
    70. SyntaxError: new keyword cannot be used with an optional chain
    71. SyntaxError: nothing to repeat
    72. SyntaxError: numbers out of order in {} quantifier.
    73. SyntaxError: octal escape sequences can't be used in untagged template literals or in strict mode code
    74. SyntaxError: parameter after rest parameter
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    77. SyntaxError: raw bracket is not allowed in regular expression with unicode flag
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    87. SyntaxError: Unexpected token
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    90. SyntaxError: use of super property/member accesses only valid within methods or eval code within methods
    91. SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead
    92. TypeError: 'caller', 'callee', and 'arguments' properties may not be accessed
    93. TypeError: 'x' is not iterable
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    99. TypeError: already executing generator
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    110. TypeError: can't set prototype: it would cause a prototype chain cycle
    111. TypeError: cannot use 'in' operator to search for 'x' in 'y'
    112. TypeError: class constructors must be invoked with 'new'
    113. TypeError: cyclic object value
    114. TypeError: derived class constructor returned invalid value x
    115. TypeError: getting private setter-only property
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    125. TypeError: Reduce of empty array with no initial value
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  14. Misc
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    4. Iteration protocols
    5. Strict mode
    6. Template literals
    7. Trailing commas
    8. Deprecated features

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