Provide JSON schema for .lintstagedrc (that can be added to schemastore)

Since .lintstagedrc is a JSON file, it can be validated if a schema is provided.

This schema could then be added to schemastore, which’d make it available on their public api for tools such as IntelliJ to download automatically.

I’m happy to attempt making such a schema if I get the time, but have created this issue for tracking, and in case someone who knows lint-staged better wants to take a crack (I’ve not actually used it yet, but love things that have schemas).

---

First whack at it, mostly accurate:

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "lint-staged configuration.",
  "description": "Run linters against staged git files and don't let 💩 slip into your code base!",
  "type": "object",
  "additionalProperties": true,
  "definitions": {
    "linter": {
      "description": " keys (String) are glob patterns, values (Array<String> | String) are commands to execute.",
      "type": [ "string", "array" ],
      "items": {
        "type": "string"
      }
    }
  },
  "properties": {
    "$schema": {
      "type": "string"
    },
    "linters": {
      "description": " keys (String) are glob patterns, values (Array<String> | String) are commands to execute.",
      "type": "object",
      "additionalProperties": {
        "type": "string"
      }
    },
    "concurrent": {
      "description": "runs linters for each glob pattern simultaneously.",
      "type": "boolean",
      "default": true
    },
    "chunkSize ": {
      "description": "Max allowed chunk size based on number of files for glob pattern. This option is only applicable on Windows based systems to avoid command length limitations.",
      "type": "number"
    },
    "globOptions": {
      "description": "micromatch options to customize how glob patterns match files.",
      "type": "object",
      "properties": {
        "matchBase": {
          "type": "boolean",
          "default": true
        },
        "dot": {
          "type": "boolean",
          "default": true
        }
      },
      "additionalProperties": true
    },
    "ignore": {
      "description": "array of glob patterns to entirely ignore from any task.",
      "type": "array",
      "items": {
        "type": "string"
      },
      "default": "['**/docs/**/*.js']"
    },
    "subTaskConcurrency": {
      "description": "Controls concurrency for processing chunks generated for each linter. This option is only applicable on Windows. Execution is not concurrent by default.",
      "type": "number",
      "default": 1
    },
    "relative": {
      "description": "If true it will give the relative path from your package.json directory to your linter arguments.",
      "type": "boolean",
      "default": false
    }
  }
}

This only supports the advanced type configuration, as I need to look into how to switch additionalProperties based on if other properties are present 😃

[G-Rath]

I added lint-staged schema to schemastore.

I’ll remove the advanced version in a few weeks, when I’ve cleared a few other things off my plate.

Q: would you be alright w/ supporting the $schema property? “support” in this case just means “ignore”.

usecase:

{
  "$schema": "http://json.schemastore.org/lintstagedrc.schema",
  "**/*.{t,j}s": "eslint",
  "**/.eslint{rc,ignore}": "npm run lint:all"
}

---

I have actually put it in the schema file for the “advanced” config, as so long as it didn’t do anything to valid that only specific properties were there, $schema shouldn’t cause problems, but it needs explicit support in the simple config since it’s pattern matching.

[G-Rath]

Finally done - took a lot of work, and most of my day, but it works:

{
  "$schema": "http://json-schema.org/draft-07/schema",
  "definitions": {
    "$schemaProperty": { "type": "string" },
    "linter": { "type": [ "string", "array" ] },
    "lintersMap": {
      "description": "keys (String) are glob patterns, values (Array<String> | String) are commands to execute.",
      "type": "object",
      "additionalProperties": {
        "$ref": "#/definitions/linter"
      }
    },
    "globOptions": {
      "description": "micromatch options to customize how glob patterns match files.",
      "type": "object",
      "properties": {
        "matchBase": {
          "type": "boolean",
          "default": true
        },
        "dot": {
          "type": "boolean",
          "default": true
        }
      },
      "additionalProperties": false
    },
    "advancedConfig": {
      "properties": {
        "$schema": { "$ref": "#/definitions/$schemaProperty" },
        "concurrent": {
          "description": "Controls if linters are run simultaneously for each glob pattern.",
          "type": "boolean",
          "default": true
        },
        "chunkSize": {
          "description": "Max allowed chunk size based on number of files for glob pattern. This option is only applicable on Windows based systems to avoid command length limitations",
          "type": "number",
          "minimum": 1
        },
        "globOptions": {
          "description": "micromatch options to customize how glob patterns match files.",
          "$ref": "#/definitions/globOptions"
        },
        "linters": {
          "description": "keys (String) are glob patterns, values (Array<String> | String) are commands to execute.",
          "$ref": "#/definitions/lintersMap"
        },
        "ignore": {
          "description": "array of glob patterns to entirely ignore from any task.",
          "type": "array",
          "items": {
            "type": "string"
          },
          "default": "['**/docs/**/*.js']"
        },
        "subTaskConcurrency": {
          "description": "Controls concurrency for processing chunks generated for each linter. This option is only applicable on Windows. Execution is not concurrent by default.",
          "type": "integer",
          "minimum": 1,
          "default": 1
        },
        "renderer": {
          "enum": [ "update", "verbose" ],
          "default": "update"
        },
        "relative": {
          "description": "If true it will give the relative path from your package.json directory to your linter arguments.",
          "type": "boolean",
          "default": false
        }
      },
      "additionalProperties": false
    },
    "basicConfig": {
      "properties": {
        "$schema": { "$ref": "#/definitions/$schemaProperty" }
      },
      "propertyNames": {
        "not": {
          "enum": [
            "concurrent",
            "chunkSize",
            "globOptions",
            "linters",
            "ignore",
            "subTaskConcurrency",
            "renderer",
            "relative"
          ]
        }
      },
      "additionalProperties": { "$ref": "#/definitions/linter" }
    }
  },
  "anyOf": [
    { "$ref": "#/definitions/advancedConfig" },
    { "$ref": "#/definitions/basicConfig" }
  ]
}

I’ll look to make a PR “soon”, along w/ automation, & ideally a test suite; all once I get the time.