30-seconds-of-code/node_modules/gatsby-source-filesystem/gatsby-node.js

"use strict";

const chokidar = require(`chokidar`);

const fs = require(`fs`);

const path = require(`path`);

const {
  Machine
} = require(`xstate`);

const {
  createFileNode
} = require(`./create-file-node`);
/**
 * Create a state machine to manage Chokidar's not-ready/ready states.
 */


const createFSMachine = () => Machine({
  key: `emitFSEvents`,
  parallel: true,
  strict: true,
  states: {
    CHOKIDAR: {
      initial: `CHOKIDAR_NOT_READY`,
      states: {
        CHOKIDAR_NOT_READY: {
          on: {
            CHOKIDAR_READY: `CHOKIDAR_WATCHING`,
            BOOTSTRAP_FINISHED: `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`
          }
        },
        CHOKIDAR_WATCHING: {
          on: {
            BOOTSTRAP_FINISHED: `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`,
            CHOKIDAR_READY: `CHOKIDAR_WATCHING`
          }
        },
        CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED: {
          on: {
            CHOKIDAR_READY: `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`
          }
        }
      }
    }
  }
});

exports.sourceNodes = ({
  actions,
  getNode,
  createNodeId,
  reporter,
  emitter
}, pluginOptions) => {
  const {
    createNode,
    createTypes,
    deleteNode
  } = actions;
  const typeDefs = `
    type File implements Node @infer {
      birthtime: Date @deprecated(reason: "Use \`birthTime\` instead")
      birthtimeMs: Float @deprecated(reason: "Use \`birthTime\` instead")
    }
  `;
  createTypes(typeDefs); // Validate that the path exists.

  if (!fs.existsSync(pluginOptions.path)) {
    reporter.panic(`
The path passed to gatsby-source-filesystem does not exist on your file system:

${pluginOptions.path}

Please pick a path to an existing directory.

See docs here - https://www.gatsbyjs.org/packages/gatsby-source-filesystem/
      `);
  } // Validate that the path is absolute.
  // Absolute paths are required to resolve images correctly.


  if (!path.isAbsolute(pluginOptions.path)) {
    pluginOptions.path = path.resolve(process.cwd(), pluginOptions.path);
  }

  const fsMachine = createFSMachine();
  let currentState = fsMachine.initialState; // Once bootstrap is finished, we only let one File node update go through
  // the system at a time.

  emitter.on(`BOOTSTRAP_FINISHED`, () => {
    currentState = fsMachine.transition(currentState.value, `BOOTSTRAP_FINISHED`);
  });
  const watcher = chokidar.watch(pluginOptions.path, {
    ignored: [`**/*.un~`, `**/.DS_Store`, `**/.gitignore`, `**/.npmignore`, `**/.babelrc`, `**/yarn.lock`, `**/bower_components`, `**/node_modules`, `../**/dist/**`, ...(pluginOptions.ignore || [])]
  });

  const createAndProcessNode = path => {
    const fileNodePromise = createFileNode(path, createNodeId, pluginOptions).then(fileNode => {
      createNode(fileNode);
      return null;
    });
    return fileNodePromise;
  }; // For every path that is reported before the 'ready' event, we throw them
  // into a queue and then flush the queue when 'ready' event arrives.
  // After 'ready', we handle the 'add' event without putting it into a queue.


  let pathQueue = [];

  const flushPathQueue = () => {
    let queue = pathQueue.slice();
    pathQueue = [];
    return Promise.all(queue.map(createAndProcessNode));
  };

  watcher.on(`add`, path => {
    if (currentState.value.CHOKIDAR !== `CHOKIDAR_NOT_READY`) {
      if (currentState.value.CHOKIDAR === `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`) {
        reporter.info(`added file at ${path}`);
      }

      createAndProcessNode(path).catch(err => reporter.error(err));
    } else {
      pathQueue.push(path);
    }
  });
  watcher.on(`change`, path => {
    if (currentState.value.CHOKIDAR === `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`) {
      reporter.info(`changed file at ${path}`);
    }

    createAndProcessNode(path).catch(err => reporter.error(err));
  });
  watcher.on(`unlink`, path => {
    if (currentState.value.CHOKIDAR === `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`) {
      reporter.info(`file deleted at ${path}`);
    }

    const node = getNode(createNodeId(path)); // It's possible the file node was never created as sometimes tools will
    // write and then immediately delete temporary files to the file system.

    if (node) {
      deleteNode({
        node
      });
    }
  });
  watcher.on(`addDir`, path => {
    if (currentState.value.CHOKIDAR !== `CHOKIDAR_NOT_READY`) {
      if (currentState.value.CHOKIDAR === `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`) {
        reporter.info(`added directory at ${path}`);
      }

      createAndProcessNode(path).catch(err => reporter.error(err));
    } else {
      pathQueue.push(path);
    }
  });
  watcher.on(`unlinkDir`, path => {
    if (currentState.value.CHOKIDAR === `CHOKIDAR_WATCHING_BOOTSTRAP_FINISHED`) {
      reporter.info(`directory deleted at ${path}`);
    }

    const node = getNode(createNodeId(path));

    if (node) {
      deleteNode({
        node
      });
    }
  });
  return new Promise((resolve, reject) => {
    watcher.on(`ready`, () => {
      currentState = fsMachine.transition(currentState.value, `CHOKIDAR_READY`);
      flushPathQueue().then(resolve, reject);
    });
  });
};

exports.setFieldsOnGraphQLNodeType = require(`./extend-file-node`);