tslint.json

{
  "rulesDirectory": ["tslint-no-unused-expression-chai"],
  // https://palantir.github.io/tslint/rules/
  "rules": {
    // TypeScript Specific

    // If the compiler is sure of the type of something, don't bother declaring
    // the type of it.
    "no-inferrable-types": true,

    // /// <reference path= is long dead; use ES6 imports for type definitions.
    "no-reference": true,

    // Use `for (value of thing)` over index based iteration.  This isn't C.
    "prefer-for-of": true,

    // Any function that returns a `Promise` should be marked `async`.  This is
    // helpful for readability, and also ensures that the function never throws
    // an exception (and instead guarantees a rejection for all errors).
    //
    // TODO: https://github.com/palantir/tslint/issues/1603
    // "promise-function-async": true,

    // We're crazy and like compressed whitespace for type declarations.  It
    // visually groups types with the variable they are annotating.
    "typedef-whitespace": [
      true,
      {
        "call-signature": "nospace",
        "index-signature": "nospace",
        "parameter": "nospace",
        "property-declaration": "nospace",
        "variable-declaration": "nospace"
      },
      {
        "call-signature": "onespace",
        "index-signature": "onespace",
        "parameter": "onespace",
        "property-declaration": "onespace",
        "variable-declaration": "onespace"
      }
    ],

    // Functionality

    // Don't use labels for evil.
    "label-position": true,

    // Use the logger configured by the project instead.
    "no-console": [
      true,
      "log",
      "info",
      "warn",
      "error",
      "dir",
      "time",
      "timeEnd",
      "trace",
      "assert"
    ],

    // new String('hi') !== 'hi' because JavaScript hates you.
    "no-construct": true,

    // Checking in statements that can block execution is generally bad.
    "no-debugger": true,

    // So rare that you need it these days; and it's so very fraught with peril.
    "no-eval": true,

    // Promises must be awaited (or then'd or caught) by default.
    // When a promise should be kicked off and not awaited (rare),
    // use void (e.g. `void promiseFn()`) to indicate this desire
    // and opt out of this rule.
    "no-floating-promises": true,

    // Iterating over an array as if it were an object leads to all sorts of "fun".
    // TODO: https://github.com/palantir/tslint/issues/1603
    // "no-for-in-array": true,

    // Shadowed variables can be pretty confusing.
    "no-shadowed-variable": true,

    // 99% of the time it's a mistake when you use fall through.
    "no-switch-case-fall-through": true,

    // Using control statements inside a finally block does crazy things.
    "no-unsafe-finally": true,

    // You probably forgot to call a method, or assign it to something.
    // (Note - we use no-unused-expression-chai instead of no-unused-expression
    // because it allows us to use chai statements like
    // `expect(thing.do).to.be.ok;` without flagging them as violations.)
    "no-unused-expression-chai": true,

    // Hoisting is not really something we need to rely on.
    "no-var-keyword": true,

    // Implicit type coercion on maths is typically a bug.
    //
    // TODO: https://github.com/palantir/tslint/issues/1603
    // "restrict-plus-operands": true

    // ¯\_(ツ)_/¯
    "triple-equals": [true, "allow-null-check"],

    // NaN !== NaN.
    "use-isnan": true,

    // Maintainability

    // So many tools bitch about missing newlines at the end of the file.
    "eofline": true,

    // Spaces.  Two of them.
    "indent": [true, "spaces"],

    // Ideally: 80 characters for comments, 120 for code.
    "max-line-length": [true, 120],

    // Trailing whitespace clutters up diffs.
    "no-trailing-whitespace": true,

    // Use let as a hint to the reader that the value will change later.
    "prefer-const": true,

    // Enforcing trailing commas reduces noise in diffs and makes mass edits
    // easier.
    "trailing-comma": [true, { "multiline": "always", "singleline": "never" }],

    // Style

    // Always use `T[]` style syntax for array types.
    "array-type": [true, "array"],

    // CamelCaps class names.
    "class-name": true,

    // A space between // and your comment aids readability.
    "comment-format": [true, "check-space"],

    // Makes object construction a bit more consistent.
    "new-parens": true,

    // Always use `as T` style type assertions; because .tsx files won't let us
    // have nice things.
    "no-angle-bracket-type-assertion": true,

    // NO.
    "no-consecutive-blank-lines": [true, 1],

    // Prefer `{ foo }` instead of `{ foo: foo }`.
    "object-literal-shorthand": true,

    // Opening and closing braces should be on the same line as statements.
    //
    //   if (true) {
    //     …
    //   } else {
    //     …
    //   }
    //
    "one-line": [
      true,
      "check-catch",
      "check-finally",
      "check-else",
      "check-open-brace",
      "check-whitespace"
    ],

    // Multi-variable declaratons tend to be very messy and hard to scan.
    "one-variable-per-declaration": [true, "ignore-for-loop"],

    // Save yourself some pain, and avoid ianm@ going OCD on your ass in PRs.
    //
    // You will probably want to turn on tslint auto fixing for your editor.
    // TODO: Until we can figure out a better way of auto fixing for everyone.
    // "ordered-imports": [true, {"import-sources-order": "case-insensitive"}],

    // We prefer single quotes.
    // TODO: We want to allow both single and backticks, but not double.
    // "quotemark": [true, "single", "avoid-escape"],

    // Why? Not sure these days, since "never" will still enforce semicolons in
    // ambiguous cases, but it's what we do.
    "semicolon": [true, "always"],

    // Use camelCase for variable names.
    "variable-name": [
      true,
      "check-format",
      "allow-leading-underscore",
      "ban-keywords",
      "allow-pascal-case"
    ],

    // Consistent whitespace around all the things!
    "whitespace": [
      true,
      "check-branch",
      "check-decl",
      "check-operator",
      "check-module",
      "check-separator",
      "check-typecast"
    ]
  }
}