JSHint error messages quick access - https://github.com/jshint/jshint/blob/2.1.4/src/shared/messages.js

messages.js

var errors = {
	// JSHint options
	E001: "Bad option: '{a}'.",
	E002: "Bad option value.",

	// JSHint input
	E003: "Expected a JSON value.",
	E004: "Input is neither a string nor an array of strings.",
	E005: "Input is empty.",
	E006: "Unexpected early end of program.",

	// Strict mode
	E007: "Missing \"use strict\" statement.",
	E008: "Strict violation.",
	E009: "Option 'validthis' can't be used in a global scope.",
	E010: "'with' is not allowed in strict mode.",

	// Constants
	E011: "const '{a}' has already been declared.",
	E012: "const '{a}' is initialized to 'undefined'.",
	E013: "Attempting to override '{a}' which is a constant.",

	// Regular expressions
	E014: "A regular expression literal can be confused with '/='.",
	E015: "Unclosed regular expression.",
	E016: "Invalid regular expression.",

	// Tokens
	E017: "Unclosed comment.",
	E018: "Unbegun comment.",
	E019: "Unmatched '{a}'.",
	E020: "Expected '{a}' to match '{b}' from line {c} and instead saw '{d}'.",
	E021: "Expected '{a}' and instead saw '{b}'.",
	E022: "Line breaking error '{a}'.",
	E023: "Missing '{a}'.",
	E024: "Unexpected '{a}'.",
	E025: "Missing ':' on a case clause.",
	E026: "Missing '}' to match '{' from line {a}.",
	E027: "Missing ']' to match '[' form line {a}.",
	E028: "Illegal comma.",
	E029: "Unclosed string.",

	// Everything else
	E030: "Expected an identifier and instead saw '{a}'.",
	E031: "Bad assignment.", // FIXME: Rephrase
	E032: "Expected a small integer or 'false' and instead saw '{a}'.",
	E033: "Expected an operator and instead saw '{a}'.",
	E034: "get/set are ES5 features.",
	E035: "Missing property name.",
	E036: "Expected to see a statement and instead saw a block.",
	E037: "Constant {a} was not declared correctly.",
	E038: "Variable {a} was not declared correctly.",
	E039: "Function declarations are not invocable. Wrap the whole function invocation in parens.",
	E040: "Each value should have its own case label.",
	E041: "Unrecoverable syntax error.",
	E042: "Stopping.",
	E043: "Too many errors.",
	E044: "'{a}' is already defined and can't be redefined.",
	E045: "Invalid for each loop.",
	E046: "A yield statement shall be within a generator function (with syntax: `function*`)",
	E047: "A generator function shall contain a yield statement.",
	E048: "Let declaration not directly within block.",
	E049: "A {a} cannot be named '{b}'."
};

var warnings = {
	W001: "'hasOwnProperty' is a really bad name.",
	W002: "Value of '{a}' may be overwritten in IE 8 and earlier.",
	W003: "'{a}' was used before it was defined.",
	W004: "'{a}' is already defined.",
	W005: "A dot following a number can be confused with a decimal point.",
	W006: "Confusing minuses.",
	W007: "Confusing pluses.",
	W008: "A leading decimal point can be confused with a dot: '{a}'.",
	W009: "The array literal notation [] is preferrable.",
	W010: "The object literal notation {} is preferrable.",
	W011: "Unexpected space after '{a}'.",
	W012: "Unexpected space before '{a}'.",
	W013: "Missing space after '{a}'.",
	W014: "Bad line breaking before '{a}'.",
	W015: "Expected '{a}' to have an indentation at {b} instead at {c}.",
	W016: "Unexpected use of '{a}'.",
	W017: "Bad operand.",
	W018: "Confusing use of '{a}'.",
	W019: "Use the isNaN function to compare with NaN.",
	W020: "Read only.",
	W021: "'{a}' is a function.",
	W022: "Do not assign to the exception parameter.",
	W023: "Expected an identifier in an assignment and instead saw a function invocation.",
	W024: "Expected an identifier and instead saw '{a}' (a reserved word).",
	W025: "Missing name in function declaration.",
	W026: "Inner functions should be listed at the top of the outer function.",
	W027: "Unreachable '{a}' after '{b}'.",
	W028: "Label '{a}' on {b} statement.",
	W030: "Expected an assignment or function call and instead saw an expression.",
	W031: "Do not use 'new' for side effects.",
	W032: "Unnecessary semicolon.",
	W033: "Missing semicolon.",
	W034: "Unnecessary directive \"{a}\".",
	W035: "Empty block.",
	W036: "Unexpected /*member '{a}'.",
	W037: "'{a}' is a statement label.",
	W038: "'{a}' used out of scope.",
	W039: "'{a}' is not allowed.",
	W040: "Possible strict violation.",
	W041: "Use '{a}' to compare with '{b}'.",
	W042: "Avoid EOL escaping.",
	W043: "Bad escaping of EOL. Use option multistr if needed.",
	W044: "Bad or unnecessary escaping.",
	W045: "Bad number '{a}'.",
	W046: "Don't use extra leading zeros '{a}'.",
	W047: "A trailing decimal point can be confused with a dot: '{a}'.",
	W048: "Unexpected control character in regular expression.",
	W049: "Unexpected escaped character '{a}' in regular expression.",
	W050: "JavaScript URL.",
	W051: "Variables should not be deleted.",
	W052: "Unexpected '{a}'.",
	W053: "Do not use {a} as a constructor.",
	W054: "The Function constructor is a form of eval.",
	W055: "A constructor name should start with an uppercase letter.",
	W056: "Bad constructor.",
	W057: "Weird construction. Is 'new' unnecessary?",
	W058: "Missing '()' invoking a constructor.",
	W059: "Avoid arguments.{a}.",
	W060: "document.write can be a form of eval.",
	W061: "eval can be harmful.",
	W062: "Wrap an immediate function invocation in parens " +
		"to assist the reader in understanding that the expression " +
		"is the result of a function, and not the function itself.",
	W063: "Math is not a function.",
	W064: "Missing 'new' prefix when invoking a constructor.",
	W065: "Missing radix parameter.",
	W066: "Implied eval. Consider passing a function instead of a string.",
	W067: "Bad invocation.",
	W068: "Wrapping non-IIFE function literals in parens is unnecessary.",
	W069: "['{a}'] is better written in dot notation.",
	W070: "Extra comma. (it breaks older versions of IE)",
	W071: "This function has too many statements. ({a})",
	W072: "This function has too many parameters. ({a})",
	W073: "Blocks are nested too deeply. ({a})",
	W074: "This function's cyclomatic complexity is too high. ({a})",
	W075: "Duplicate key '{a}'.",
	W076: "Unexpected parameter '{a}' in get {b} function.",
	W077: "Expected a single parameter in set {a} function.",
	W078: "Setter is defined without getter.",
	W079: "Redefinition of '{a}'.",
	W080: "It's not necessary to initialize '{a}' to 'undefined'.",
	W081: "Too many var statements.",
	W082: "Function declarations should not be placed in blocks. " +
		"Use a function expression or move the statement to the top of " +
		"the outer function.",
	W083: "Don't make functions within a loop.",
	W084: "Expected a conditional expression and instead saw an assignment.",
	W085: "Don't use 'with'.",
	W086: "Expected a 'break' statement before '{a}'.",
	W087: "Forgotten 'debugger' statement?",
	W088: "Creating global 'for' variable. Should be 'for (var {a} ...'.",
	W089: "The body of a for in should be wrapped in an if statement to filter " +
		"unwanted properties from the prototype.",
	W090: "'{a}' is not a statement label.",
	W091: "'{a}' is out of scope.",
	W092: "Wrap the /regexp/ literal in parens to disambiguate the slash operator.",
	W093: "Did you mean to return a conditional instead of an assignment?",
	W094: "Unexpected comma.",
	W095: "Expected a string and instead saw {a}.",
	W096: "The '{a}' key may produce unexpected results.",
	W097: "Use the function form of \"use strict\".",
	W098: "'{a}' is defined but never used.",
	W099: "Mixed spaces and tabs.",
	W100: "This character may get silently deleted by one or more browsers.",
	W101: "Line is too long.",
	W102: "Trailing whitespace.",
	W103: "The '{a}' property is deprecated.",
	W104: "'{a}' is only available in JavaScript 1.7.",
	W105: "Unexpected {a} in '{b}'.",
	W106: "Identifier '{a}' is not in camel case.",
	W107: "Script URL.",
	W108: "Strings must use doublequote.",
	W109: "Strings must use singlequote.",
	W110: "Mixed double and single quotes.",
	W112: "Unclosed string.",
	W113: "Control character in string: {a}.",
	W114: "Avoid {a}.",
	W115: "Octal literals are not allowed in strict mode.",
	W116: "Expected '{a}' and instead saw '{b}'.",
	W117: "'{a}' is not defined.",
	W118: "'{a}' is only available in Mozilla JavaScript extensions (use moz option).",
	W119: "'{a}' is only available in ES6 (use esnext option)."
};

var info = {
	I001: "Comma warnings can be turned off with 'laxcomma'.",
	I002: "Reserved words as properties can be used under the 'es5' option.",
	I003: "ES5 option is now set per default"
};