scottarver/tslint-etc

More rules for TSLint

tslint-etc

What is it?

tslint-etc is set of TSLint rules to enforce policies that cannot be specified - or easily specified - with the built-in rules.

Install

Install the package using NPM:

npm install tslint-etc --save-dev

Update your tslint.json file to extend this package and add any rules you want to configure to the rules object:

{
  "extends": [
    "tslint-etc"
  ],
  "rules": {
    "throw-error": { "severity": "error" }
  }
}

Rules

WARNING: Before configuring any of the following rules, you should ensure that TSLint's no-unused-variable rule is not enabled in your configuration (or in any configuration that you extend). That rule has caused problems in the past - as it leaves the TypeScript program in an unstable state - and has a significant number of still-open issues. Consider using this package's no-unused-declaration rule instead.

The package includes the following rules (none of which are enabled by default):

Rule	Description	Fixer	Options
ban-imports	Disallows the use of banned imports.	No	See below
no-assign-mutated-array	Disallows the assignment of returned, mutated arrays. Useful for those times you forget that sort and reverse mutate the array upon which they are called.	No	None
no-missing-dollar-expect	Disallows dtslint $ExpectType and $ExpectError expectations if the $ is missing.	No	None
no-unsafe-callback-scope	Disallows the use of variables/properties from unsafe/outer scopes in callbacks.	No	None
no-unused-declaration	Disallows unused declarations.	Yes, but see below	See below
throw-error	Enforces the use of Error values when throwing or rejecting.	No	None

Options and notes

ban-imports

The ban-imports rule takes an object containing keys that are regular expressions and values that are either booleans or strings containing the explanation for the ban.

For example, to following configuration would disallow "foo" with an explanation, would disallow "bar" without an explanation and would allow "baz":

"rules": {
  "ban-imports": {
    "options": [{
      "^foo$": "'foo' has been deprecated; use 'baz'",
      "^bar$": true,
      "^baz$": false
    }],
    "severity": "error"
  }
}

no-unused-declaration

This rule has a fixer. However, the fixer will only remove unused import declarations. It will not remove other kinds of declarations, as doing so could be potentially destructive.

For example, having it remove a function that you've spent time writing - just because you've not yet exported or called it - would be too dispiriting, so the rule will just flag it as a failure and leave the function untouched.

The rule takes an optional object with optional imports and declarations properties. The properties are booleans and determine whether or unused imports or declarations are allowed. The properties default to true.

For example:

"rules": {
  "no-unused-declaration": {
    "options": [{
      "declarations": true,
      "imports": true
    }],
    "severity": "error"
  }
}