| init-declarations |
Enforce or disallow variable initializations at definition |
var foo = 1;
var bar;
bar = 2;
|
Off |
[Link](http://eslint.org/docs/rules/init-declarations) |
| no-catch-shadow |
Disallow the catch clause parameter name being the same as a variable in the outer scope |
var err = "x";
try {
throw "problem";
} catch (err) {}
console.log(err) // err is 'problem', not 'x'
|
Off |
[Link](http://eslint.org/docs/rules/no-catch-shadow) |
| no-delete-var |
Disallow deletion of variables |
var x;
delete x;
|
Error |
[Link](http://eslint.org/docs/rules/no-delete-var) |
| no-label-var |
Disallow labels that share a name with a variable |
var x = foo;
function bar() {
x:
for (;;) {
break x;
}
}
|
Off |
[Link](http://eslint.org/docs/rules/no-label-var) |
| no-shadow-restricted-names |
Disallow shadowing of names such as `arguments` |
var undefined = "foo";
!function(Infinity){};
function NaN(){}
|
Off |
[Link](http://eslint.org/docs/rules/no-shadow-restricted-names) |
| no-shadow |
Disallow declaration of variables already declared in the outer scope |
var a = 3;
function b() {
var a = 10;
}
|
Off |
[Link](http://eslint.org/docs/rules/no-shadow) |
| no-undef-init |
Disallow use of undefined when initializing variables |
// Bad
var foo = undefined;
// Good
var foo;
console.log(foo === undefined); // true
|
Off |
[Link](http://eslint.org/docs/rules/no-undef-init) |
| no-undef |
Disallow use of undeclared variables unless mentioned in a `/*global */` block |
var a = someFunction(); // 'someFunction' is not defined.
b = 10; // 'b' is not defined.
|
Error |
[Link](http://eslint.org/docs/rules/no-undef) |
| no-undefined |
Disallow use of `undefined` variable |
var undefined = "hi";
|
Off |
[Link](http://eslint.org/docs/rules/no-undefined) |
| no-unused-vars |
Disallow declaration of variables that are not used in the code |
var y = 10;
y = 5;
// By default, unused arguments cause warnings.
(function(foo) {
return 5;
})();
|
Error |
[Link](http://eslint.org/docs/rules/no-unused-vars) |
| no-use-before-define |
Disallow use of variables before they are defined |
alert(a);
var a = 10;
f();
function f() {}
|
Off |
[Link](http://eslint.org/docs/rules/no-use-before-define) |