quick-lint-js

Error codes

quick-lint-js can find the following warnings and errors in your code:

• E0001: variable assigned before its declaration
• E0002: assignment to const global variable
• E0003: assignment to const variable
• E0004: assignment to const variable before its declaration
• E0005: BigInt literal contains decimal point
• E0006: BigInt literal contains exponent
• E0007: classes cannot be named 'let'
• E0008: let statement cannot declare variables named 'let'
• E0009: cannot export variable named 'let'
• E0010: cannot import 'let'
• E0011: character is not allowed in identifiers
• E0012: escaped character is not allowed in identifiers
• E0013: code point out of range
• E0014: expected expression before newline
• E0015: expected expression before semicolon
• E0016: expected hexadecimal digits in Unicode escape sequence
• E0017: if statement needs parentheses around condition
• E0018: if statement is missing '(' or ')' around condition
• E0019: escaping '-' is not allowed in tag names; write '-' instead
• E0020: invalid expression left of assignment
• E0021: invalid lone literal in object literal
• E0022: invalid UTF-8 sequence
• E0023: keywords cannot contain escape sequences
• E0024: const/let/var with no bindings
• E0025: missing comma between object literal entries
• E0026: missing operand for operator
• E0027: missing semicolon after statement
• E0028: number literal contains consecutive underscores
• E0029: number literal contains trailing underscores
• E0030: octal literal may not have exponent
• E0031: octal literal may not have decimal
• E0032: legacy octal literal may not be BigInt
• E0033: redeclaration of global variable
• E0034: redeclaration of variable
• E0035: RegExp literal flags cannot contain Unicode escapes
• E0036: stray comma in let statement
• E0037: unclosed block comment
• E0038: unclosed identifier escape sequence
• E0039: unclosed regexp literal
• E0040: unclosed string literal
• E0041: unclosed template
• E0042: unexpected '@'
• E0043: unexpected '\' in identifier
• E0044: unexpected characters in number literal
• E0045: unexpected control character
• E0046: unexpected characters in binary literal
• E0047: unexpected characters in octal literal
• E0048: unexpected characters in hex literal
• E0049: binary number literal has no digits
• E0050: hex number literal has no digits
• E0051: octal number literal has no digits
• E0052: unexpected '#'
• E0053: missing property name between '.' and '.'
• E0054: unexpected token
• E0055: unmatched indexing bracket
• E0056: unmatched parenthesis
• E0057: use of undeclared variable
• E0058: variable used before declaration
• E0059: assignment to undeclared variable
• E0060: invalid hex escape sequence
• E0061: missing name in function statement
• E0062: missing name or parentheses for function
• E0063: missing operator between expression and arrow function
• E0064: missing body for 'if' statement
• E0065: 'else' has no corresponding 'if'
• E0066: exporting requires '{' and '}'
• E0067: exporting requires 'default'
• E0068: extra ',' is not allowed between function call arguments
• E0069: cannot declare 'await' inside async function
• E0070: commas are not allowed after spread parameter
• E0071: cannot declare 'yield' inside generator function
• E0072: methods should not use the 'function' keyword
• E0073: missing function parameter list
• E0074: '.' operator needs a key name; use + to concatenate strings; use [] to access with a dynamic key
• E0075: indexing requires an expression
• E0076: cannot declare and export variable with 'export default'
• E0077: function call before declaration in blocked scope
• E0078: missing expression between parentheses
• E0079: missing name of exported function
• E0080: missing name of class
• E0081: missing name of exported class
• E0082: assigning to 'async' in a for-of loop requires parentheses
• E0083: missing value for object property
• E0084: do-while loop needs parentheses around condition
• E0085: do-while loop is missing '(' or ')' around condition
• E0086: redundant delete statement on variable
• E0087: while loop needs parentheses around condition
• E0088: while loop is missing '(' or ')' around condition
• E0089: with statement needs parentheses around expression
• E0090: with statement is missing '(' or ')' around expression
• E0091: switch statement needs parentheses around condition
• E0092: switch statement is missing '(' or ')' around condition
• E0093: C-style for loop is missing its third component
• E0094: missing body for 'for' loop
• E0095: Unicode byte order mark (BOM) cannot appear before #! at beginning of script
• E0096: missing for loop header
• E0097: for loop needs an iterable, or condition and update clauses
• E0098: for loop needs an iterable, or condition and update clauses
• E0099: missing semicolon between init and condition parts of for loop
• E0100: missing semicolon between condition and update parts of for loop
• E0101: missing body for do-while loop
• E0102: C-style for loops have only three semicolon-separated components
• E0103: missing 'while (condition)' for do-while statement
• E0104: missing body for while loop
• E0105: missing parameters for arrow function
• E0106: missing body for 'switch' statement
• E0107: expected '{'
• E0108: 'in' disallowed in C-style for loop initializer
• E0109: for-of loop expression cannot have semicolons
• E0110: for-in loop expression cannot have semicolons
• E0111: missing body for class
• E0112: unexpected token in export; expected 'export default ...' or 'export {name}' or 'export * from ...' or 'export class' or 'export function' or 'export let'
• E0113: incomplete export; expected 'export default ...' or 'export {name}' or 'export * from ...' or 'export class' or 'export function' or 'export let'
• E0114: unexpected token in variable declaration; expected variable name
• E0115: unexpected 'case' outside switch statement
• E0116: unexpected 'default' outside switch statement
• E0117: unexpected 'catch' without 'try'
• E0118: unexpected 'finally' without 'try'
• E0119: missing body for catch clause
• E0120: missing body for try statement
• E0121: missing body for finally clause
• E0122: missing catch or finally clause for try statement
• E0123: missing variable name
• E0124: cannot declare variable named keyword
• E0125: missing header and body for 'for' loop
• E0126: expected 'as' between '*' and variable
• E0127: TypeScript's 'enum' feature is not yet implemented by quick-lint-js
• E0128: expected 'from' before module specifier
• E0129: expected 'from "name_of_module.mjs"'
• E0130: missing catch variable name between parentheses
• E0131: expected ',' between object literal entries
• E0132: missing ',' between variable declarations
• E0133: error generator function star belongs before name
• E0134: unclosed code block; expected '}' by end of file
• E0135: expected variable name for 'catch'
• E0136: cannot update variable with '+=' while declaring it
• E0137: missing condition for switch statement
• E0138: missing condition for if statement
• E0139: missing condition for while statement
• E0140: expected expression after 'case'
• E0141: expected ')' to close function call
• E0142: missing property name after '.' operator
• E0143: unmatched '}'
• E0144: cannot export variable named keyword
• E0145: cannot import variable named keyword
• E0146: missing ':' in conditional expression
• E0147: unexpected identifier in expression; missing operator before
• E0148: missing body for statement; a function statement is not allowed as the body of statement
• E0149: missing body for statement; a class statement is not allowed as the body of statement
• E0150: missing body for statement; a lexical declaration is not allowed as the body of statement
• E0151: invalid function parameter
• E0152: legacy octal literals may not contain underscores
• E0153: forwarding exports are only allowed in export-from
• E0154: unexpected expression; missing key for object entry
• E0155: cannot reference private variables without object; use 'this.'
• E0156: private properties are not allowed in object literals
• E0157: missing end of array; expected ']'
• E0158: unexpected '=>'; expected parameter for arrow function, but got a literal instead
• E0159: unexpected literal in parameter list; expected parameter name
• E0160: unexpected '=>'; expected parameter for arrow function, but got an expression instead
• E0161: unclosed object literal; expected '}'
• E0162: 'await' is only allowed in async functions
• E0163: newline is not allowed between 'async' and arrow function parameter list
• E0164: JSON syntax error
• E0165: TypeScript style const field
• E0166: "globals" descriptor "shadowable" property must be a boolean
• E0167: "globals" descriptor "writable" property must be a boolean
• E0168: "globals" must be an object
• E0169: "global-groups" must be a boolean or an array
• E0170: "global-groups" entries must be strings
• E0171: "globals" descriptor must be a boolean or an object
• E0172: missing body for function
• E0173: cannot assign to loop variable in for of/in loop
• E0174: functions/methods should not have '=>'
• E0175: expected variable name for 'import'-'as'
• E0176: missing arrow operator for arrow function
• E0177: React/JSX is not yet implemented
• E0178: 'await' cannot be followed by an arrow function; use 'async' instead
• E0179: return statement returns nothing (undefined)
• E0180: stray comma in function parameter
• E0181: unclosed string literal
• E0182: '>' is not allowed directly in JSX text; write {'>'} or > instead
• E0183: '}' is not allowed directly in JSX text; write {'}'} instead
• E0184: missing 'if' after 'else'
• E0185: assignment to imported variable; imported variable declared here
• E0186: missing '...' in JSX attribute spread
• E0187: mismatched JSX tags; expected </foo>
• E0188: '=' changes variables; to compare, use '===' instead
• E0189: missing '<>' and '</>' to enclose multiple children
• E0190: missing comparison; '===' does not extend to the right side of '||'
• E0191: event attributes must be camelCase
• E0192: attribute has wrong capitalization
• E0193: misspelled React attribute; write 'className' instead
• E0194: missing parentheses around left-hand side of **; ** operator cannot be used after unary - without parentheses
• E0195: missing parentheses around operand of typeof; typeof operator cannot be used before ** without parentheses
• E0196: new variable shadows existing variable
• E0197: '“' is not allowed for strings; use " instead
• E0199: unclosed class; expected '}' by end of file
• E0200: break can only be used inside of a loop or switch
• E0201: continue can only be used inside of a loop
• E0202: missing '=' after variable
• E0203: depth limit exceeded
• E0204: error generator function star belongs after keyword function
• E0205: error missing initializer in const declaration
• E0206: label named 'await' not allowed in async function
• E0207: code point in Unicode escape sequence must not be greater than U+10FFFF
• E0208: cannot access private identifier outside class
• E0209: commas are not allowed between class methods
• E0210: unopened block comment
• E0211: missing parentheses around self-invoked function
• E0269: 'async static' is not allowed; write 'static async' instead