makemeahanzi/server/migration.js

"use strict";

const completionCallback = undefined;

const perGlyphCallback = (glyph) => {
  assert(glyph.stages.strokes !== undefined);
  let changed = 0;
  for (var i = 0; i < glyph.stages.strokes.length; i++) {
    const stroke = glyph.stages.strokes[i];
    const paths = svg.convertSVGPathToPaths(stroke);
    assert(paths.length === 1);
    const path = svg.convertPathsToSVGPath(paths);
    if (path !== stroke) {
      glyph.stages.strokes[i] = path;
      changed += 1;
    }
  }
  if (changed) {
    console.log(`Flipped ${changed} path(s) in glyph: ${glyph.character}`);
  }
}

// Runs the given per-glyph callback for each glyph in the database.
// When all the glyphs are migrated, runs the completion callback.
const runMigration = () => {
  console.log('Running migration...');
  if (perGlyphCallback) {
    const codepoints =
        Glyphs.find({}, {fields: {codepoint: 1}, sort: {codepoint: 1}}).fetch();
    for (let i = 0; i < codepoints.length; i++) {
      const glyph = Glyphs.findOne({codepoint: codepoints[i].codepoint});
      assert(glyph, 'Glyphs changed during migration!');
      perGlyphCallback(glyph);
      if ((i + 1) % 1000 === 0) {
        console.log(`Migrated ${i + 1} glyphs.`);
      }
    }
  }
  if (completionCallback) {
    completionCallback();
  }
  console.log('Migration complete.');
}

Meteor.startup(() => {
  if (!perGlyphCallback && !completionCallback) {
    return;
  }
  console.log('Preparing for migration...');
  cjklib.promise.then(Meteor.bindEnvironment(runMigration))
                .catch(console.error.bind(console));
});