<a href="http://json-schema.org">
  <img width="160" height="160"
    src="https://raw.githubusercontent.com/webpack-contrib/schema-utils/master/.github/assets/logo.png">
</a>
<a href="https://github.com/webpack/webpack">
  <img width="200" height="200"
    src="https://webpack.js.org/assets/icon-square-big.svg">
</a>

console
npm install schema-utils

json
{
  "type": "object",
  "properties": {
    "option": {
      "type": "boolean"
    }
  },
  "additionalProperties": false
}

js
import schema from "./path/to/schema.json";
import { validate } from "schema-utils";

const options = { option: true };
const configuration = { name: "Loader Name/Plugin Name/Name" };

validate(schema, options, configuration);

json
{
  "type": "object",
  "properties": {
    "name": {
      "description": "This is description of option.",
      "type": "string"
    }
  },
  "additionalProperties": false
}

js
import schema from "./path/to/schema.json";
import { validate } from "schema-utils";

const options = { foo: "bar" };

validate(schema, { name: 123 }, { name: "MyPlugin" });

json
{
  "title": "My Loader options",
  "type": "object",
  "properties": {
    "name": {
      "description": "This is description of option.",
      "type": "string"
    }
  },
  "additionalProperties": false
}

js
import schema from "./path/to/schema.json";
import { validate } from "schema-utils";

const options = { foo: "bar" };

validate(schema, options, { name: "MyPlugin" });

shell
Invalid configuration object. MyPlugin has been initialised using a configuration object that does not match the API schema.
 - configuration.optionName should be a integer.

js
import schema from "./path/to/schema.json";
import { validate } from "schema-utils";

const options = { foo: "bar" };

validate(schema, options, { name: "MyPlugin", baseDataPath: "options" });

shell
Invalid options object. MyPlugin has been initialised using an options object that does not match the API schema.
 - options.optionName should be a integer.

js
import schema from "./path/to/schema.json";
import { validate } from "schema-utils";

const options = { foo: "bar" };

validate(schema, options, {
  name: "MyPlugin",
  postFormatter: (formattedError, error) => {
    if (error.keyword === "type") {
      return `${formattedError}\nAdditional Information.`;
    }

    return formattedError;
  },
});

shell
Invalid options object. MyPlugin has been initialized using an options object that does not match the API schema.
 - options.optionName should be a integer.
   Additional Information.

json
{
  "type": "object",
  "properties": {
    "name": {
      "type": "string"
    },
    "test": {
      "anyOf": [
        { "type": "array" },
        { "type": "string" },
        { "instanceof": "RegExp" }
      ]
    },
    "transform": {
      "instanceof": "Function"
    },
    "sourceMap": {
      "type": "boolean"
    }
  },
  "additionalProperties": false
}

js
import { getOptions } from "loader-utils";
import { validate } from "schema-utils";

import schema from "path/to/schema.json";

function loader(src, map) {
  const options = getOptions(this);

  validate(schema, options, {
    name: "Loader Name",
    baseDataPath: "options",
  });

  // Code...
}

export default loader;

js
import { validate } from "schema-utils";

import schema from "path/to/schema.json";

class Plugin {
  constructor(options) {
    validate(schema, options, {
      name: "Plugin Name",
      baseDataPath: "options",
    });

    this.options = options;
  }

  apply(compiler) {
    // Code...
  }
}

export default Plugin;