transform-sort-imports.js

const order = [
  /^lib\//,
  /^actions\//,
  /^reducers\//,
  /^constants\//,
  /^containers\//,
  /^components\//,
  /^schema\/[A-Z]/,
  /^schema\//,
  /^\.\.?\/[A-Z]/,
  /^\.\.?\//,
];

function pos(s) {
  for (let i = 0; i < order.length; i++) {
    if (order[i].test(s)) {
      return i;
    }
  }

  return -1;
}

function cmp(a, b) {
  const posA = pos(a.source.value);
  const posB = pos(b.source.value);

  if (posA < posB) { return -1; }
  if (posA > posB) { return 1; }

  if (a.source.value < b.source.value) { return -1; }
  if (a.source.value > b.source.value) { return 1; }

  return 0;
}

export default function(file, api) {
  const j = api.jscodeshift;

  function printImports(a) {
    const bits = [];

    let lastPos = null;
    a.forEach((n) => {
      const p = pos(n.source.value);

      if (p !== lastPos) {
        if (lastPos !== null) {
          bits.push('');
        }

        lastPos = p;
      }

      bits.push(j(n).toSource());
      if (n.source.value.indexOf('actions/') === 0) {
        bits.push('');
      }
    });

    return bits.join('\n').replace(/\n\n\n+/g, '\n\n').trim();
  }

  let h = null;
  const f = j(file.source);

  f.find(j.Program).forEach((p) => {
    const imports = p.value.body.filter((e) => e.type === 'ImportDeclaration');
    let leadingComments = null;

    if (imports.length > 0) {
      // make sure top-of-file comments stay where they are
      leadingComments = p.value.body[0].leadingComments;
      delete p.value.body[0].leadingComments;
      delete p.value.body[0].comments;
    }

    p.value.body = p.value.body.filter((e) => e.type !== 'ImportDeclaration');

    imports.sort(cmp);

    if (imports.length > 0) {
      imports[0].leadingComments = leadingComments;
      imports[0].comments = leadingComments;
    }

    h = printImports(imports);
  });

  if (h.length > 0) {
    return h + '\n\n' + f.toSource();
  }

  return null;
}