parcel-bundler/lib/scope-hoisting/hoist.js

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _slicedToArray2 = _interopRequireDefault(require("@babel/runtime/helpers/slicedToArray"));

const path = require('path');

const mm = require('micromatch');

const t = require('@babel/types');

const template = require('@babel/template').default;

const rename = require('./renamer');

const _require = require('./utils'),
      getName = _require.getName,
      getIdentifier = _require.getIdentifier,
      getExportIdentifier = _require.getExportIdentifier;

const WRAPPER_TEMPLATE = template(`
  var NAME = (function () {
    var exports = this;
    var module = {exports: this};
    BODY;
    return module.exports;
  }).call({});
`);
const ESMODULE_TEMPLATE = template(`exports.__esModule = true;`);
const EXPORT_ASSIGN_TEMPLATE = template('EXPORTS.NAME = LOCAL');
const EXPORT_ALL_TEMPLATE = template('$parcel$exportWildcard(OLD_NAME, $parcel$require(ID, SOURCE))');
const REQUIRE_CALL_TEMPLATE = template('$parcel$require(ID, SOURCE)');
const REQUIRE_RESOLVE_CALL_TEMPLATE = template('$parcel$require$resolve(ID, SOURCE)');
const TYPEOF = {
  module: 'object',
  require: 'function'
};

function hasSideEffects(asset, {
  sideEffects
} = asset._package) {
  switch (typeof sideEffects) {
    case 'undefined':
      return true;

    case 'boolean':
      return sideEffects;

    case 'string':
      return mm.isMatch(path.relative(asset._package.pkgdir, asset.name), sideEffects, {
        matchBase: true
      });

    case 'object':
      return sideEffects.some(sideEffects => hasSideEffects(asset, {
        sideEffects
      }));
  }
}

module.exports = {
  Program: {
    enter(path, asset) {
      path.scope.crawl();
      asset.cacheData.imports = asset.cacheData.imports || Object.create(null);
      asset.cacheData.exports = asset.cacheData.exports || Object.create(null);
      asset.cacheData.wildcards = asset.cacheData.wildcards || [];
      asset.cacheData.sideEffects = asset._package && hasSideEffects(asset);
      let shouldWrap = false;
      path.traverse({
        CallExpression(path) {
          // If we see an `eval` call, wrap the module in a function.
          // Otherwise, local variables accessed inside the eval won't work.
          let callee = path.node.callee;

          if (t.isIdentifier(callee) && callee.name === 'eval' && !path.scope.hasBinding('eval', true)) {
            asset.cacheData.isCommonJS = true;
            shouldWrap = true;
            path.stop();
          }
        },

        ReturnStatement(path) {
          // Wrap in a function if we see a top-level return statement.
          if (!path.getFunctionParent()) {
            shouldWrap = true;
            asset.cacheData.isCommonJS = true;
            path.replaceWith(t.returnStatement(t.memberExpression(t.identifier('module'), t.identifier('exports'))));
            path.stop();
          }
        },

        ReferencedIdentifier(path) {
          // We must wrap if `module` is referenced as a free identifier rather
          // than a statically resolvable member expression.
          if (path.node.name === 'module' && (!path.parentPath.isMemberExpression() || path.parent.computed) && !(path.parentPath.isUnaryExpression() && path.parent.operator === 'typeof') && !path.scope.hasBinding('module') && !path.scope.getData('shouldWrap')) {
            asset.cacheData.isCommonJS = true;
            shouldWrap = true;
            path.stop();
          }
        }

      });
      path.scope.setData('shouldWrap', shouldWrap);
    },

    exit(path, asset) {
      let scope = path.scope;

      if (scope.getData('shouldWrap')) {
        if (asset.cacheData.isES6Module) {
          path.unshiftContainer('body', [ESMODULE_TEMPLATE()]);
        }

        path.replaceWith(t.program([WRAPPER_TEMPLATE({
          NAME: getExportsIdentifier(asset),
          BODY: path.node.body
        })]));
        asset.cacheData.exports = {};
        asset.cacheData.isCommonJS = true;
        asset.cacheData.isES6Module = false;
      } else {
        // Re-crawl scope so we are sure to have all bindings.
        scope.crawl(); // Rename each binding in the top-level scope to something unique.

        for (let name in scope.bindings) {
          if (!name.startsWith('$' + t.toIdentifier(asset.id))) {
            let newName = getName(asset, 'var', name);
            rename(scope, name, newName);
          }
        }

        let exportsIdentifier = getExportsIdentifier(asset); // Add variable that represents module.exports if it is referenced and not declared.

        if (scope.hasGlobal(exportsIdentifier.name) && !scope.hasBinding(exportsIdentifier.name)) {
          scope.push({
            id: exportsIdentifier,
            init: t.objectExpression([])
          });
        }
      }

      path.stop();
      asset.isAstDirty = true;
    }

  },

  DirectiveLiteral(path) {
    // Remove 'use strict' directives, since modules are concatenated - one strict mode
    // module should not apply to all other modules in the same scope.
    if (path.node.value === 'use strict') {
      path.parentPath.remove();
    }
  },

  MemberExpression(path, asset) {
    if (path.scope.hasBinding('module') || path.scope.getData('shouldWrap')) {
      return;
    }

    if (t.matchesPattern(path.node, 'module.exports')) {
      path.replaceWith(getExportsIdentifier(asset));
      asset.cacheData.isCommonJS = true;
    }

    if (t.matchesPattern(path.node, 'module.id')) {
      path.replaceWith(t.stringLiteral(asset.id));
    }

    if (t.matchesPattern(path.node, 'module.hot')) {
      path.replaceWith(t.identifier('null'));
    }

    if (t.matchesPattern(path.node, 'module.bundle')) {
      path.replaceWith(t.identifier('require'));
    }
  },

  ReferencedIdentifier(path, asset) {
    if (path.node.name === 'exports' && !path.scope.hasBinding('exports') && !path.scope.getData('shouldWrap')) {
      path.replaceWith(getExportsIdentifier(asset));
      asset.cacheData.isCommonJS = true;
    }

    if (path.node.name === 'global' && !path.scope.hasBinding('global')) {
      path.replaceWith(t.identifier('$parcel$global'));
      asset.globals.delete('global');
    }

    let globalCode = asset.globals.get(path.node.name);

    if (globalCode) {
      path.scope.getProgramParent().path.unshiftContainer('body', [template(globalCode)()]);
      asset.globals.delete(path.node.name);
    }
  },

  ThisExpression(path, asset) {
    if (!path.scope.parent && !path.scope.getData('shouldWrap')) {
      path.replaceWith(getExportsIdentifier(asset));
      asset.cacheData.isCommonJS = true;
    }
  },

  AssignmentExpression(path, asset) {
    if (path.scope.hasBinding('exports') || path.scope.getData('shouldWrap')) {
      return;
    }

    let _path$node = path.node,
        left = _path$node.left,
        right = _path$node.right;

    if (t.isIdentifier(left) && left.name === 'exports') {
      path.get('left').replaceWith(getExportsIdentifier(asset));
      asset.cacheData.isCommonJS = true;
    } // If we can statically evaluate the name of a CommonJS export, create an ES6-style export for it.
    // This allows us to remove the CommonJS export object completely in many cases.


    if (t.isMemberExpression(left) && t.isIdentifier(left.object, {
      name: 'exports'
    }) && (t.isIdentifier(left.property) && !left.computed || t.isStringLiteral(left.property))) {
      let name = t.isIdentifier(left.property) ? left.property.name : left.property.value;
      let identifier = getExportIdentifier(asset, name); // Replace the CommonJS assignment with a reference to the ES6 identifier.

      path.get('left.object').replaceWith(getExportsIdentifier(asset));
      path.get('right').replaceWith(identifier); // If this is the first assignment, create a binding for the ES6-style export identifier.
      // Otherwise, assign to the existing export binding.

      let scope = path.scope.getProgramParent();

      if (!scope.hasBinding(identifier.name)) {
        asset.cacheData.exports[name] = identifier.name;

        let _path$insertBefore = path.insertBefore(t.variableDeclaration('var', [t.variableDeclarator(t.clone(identifier), right)])),
            _path$insertBefore2 = (0, _slicedToArray2.default)(_path$insertBefore, 1),
            decl = _path$insertBefore2[0];

        scope.registerDeclaration(decl);
      } else {
        path.insertBefore(t.assignmentExpression('=', t.clone(identifier), right));
      }

      asset.cacheData.isCommonJS = true;
    }
  },

  UnaryExpression(path) {
    // Replace `typeof module` with "object"
    if (path.node.operator === 'typeof' && t.isIdentifier(path.node.argument) && TYPEOF[path.node.argument.name] && !path.scope.hasBinding(path.node.argument.name) && !path.scope.getData('shouldWrap')) {
      path.replaceWith(t.stringLiteral(TYPEOF[path.node.argument.name]));
    }
  },

  CallExpression(path, asset) {
    let _path$node2 = path.node,
        callee = _path$node2.callee,
        args = _path$node2.arguments;
    let ignore = args.length !== 1 || !t.isStringLiteral(args[0]) || path.scope.hasBinding('require');

    if (ignore) {
      return;
    }

    if (t.isIdentifier(callee, {
      name: 'require'
    })) {
      let source = args[0].value; // Ignore require calls that were ignored earlier.

      if (!asset.dependencies.has(source)) {
        return;
      } // If this require call does not occur in the top-level, e.g. in a function
      // or inside an if statement, or if it might potentially happen conditionally,
      // the module must be wrapped in a function so that the module execution order is correct.


      let parent = path.getStatementParent().parentPath;
      let bail = path.findParent(p => p.isConditionalExpression() || p.isLogicalExpression() || p.isSequenceExpression());

      if (!parent.isProgram() || bail) {
        asset.dependencies.get(source).shouldWrap = true;
      }

      asset.cacheData.imports['$require$' + source] = [source, '*']; // Generate a variable name based on the current asset id and the module name to require.
      // This will be replaced by the final variable name of the resolved asset in the packager.

      path.replaceWith(REQUIRE_CALL_TEMPLATE({
        ID: t.stringLiteral(asset.id),
        SOURCE: t.stringLiteral(args[0].value)
      }));
    }

    if (t.matchesPattern(callee, 'require.resolve')) {
      path.replaceWith(REQUIRE_RESOLVE_CALL_TEMPLATE({
        ID: t.stringLiteral(asset.id),
        SOURCE: args[0]
      }));
    }
  },

  ImportDeclaration(path, asset) {
    // For each specifier, rename the local variables to point to the imported name.
    // This will be replaced by the final variable name of the resolved asset in the packager.
    var _iteratorNormalCompletion = true;
    var _didIteratorError = false;
    var _iteratorError = undefined;

    try {
      for (var _iterator = path.node.specifiers[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
        let specifier = _step.value;
        let id = getIdentifier(asset, 'import', specifier.local.name);
        rename(path.scope, specifier.local.name, id.name);

        if (t.isImportDefaultSpecifier(specifier)) {
          asset.cacheData.imports[id.name] = [path.node.source.value, 'default'];
        } else if (t.isImportSpecifier(specifier)) {
          asset.cacheData.imports[id.name] = [path.node.source.value, specifier.imported.name];
        } else if (t.isImportNamespaceSpecifier(specifier)) {
          asset.cacheData.imports[id.name] = [path.node.source.value, '*'];
        }
      }
    } catch (err) {
      _didIteratorError = true;
      _iteratorError = err;
    } finally {
      try {
        if (!_iteratorNormalCompletion && _iterator.return != null) {
          _iterator.return();
        }
      } finally {
        if (_didIteratorError) {
          throw _iteratorError;
        }
      }
    }

    addImport(asset, path);
    path.remove();
  },

  ExportDefaultDeclaration(path, asset) {
    let declaration = path.node.declaration;
    let identifier = getExportIdentifier(asset, 'default');
    let name = declaration.id ? declaration.id.name : declaration.name;

    if (asset.cacheData.imports[name]) {
      asset.cacheData.exports['default'] = asset.cacheData.imports[name];
      identifier = t.identifier(name);
    }

    if (hasExport(asset, name)) {
      identifier = t.identifier(name);
    } // Add assignment to exports object for namespace imports and commonjs.


    path.insertAfter(EXPORT_ASSIGN_TEMPLATE({
      EXPORTS: getExportsIdentifier(asset, path.scope),
      NAME: t.identifier('default'),
      LOCAL: t.clone(identifier)
    }));

    if (t.isIdentifier(declaration)) {
      // Rename the variable being exported.
      safeRename(path, asset, declaration.name, identifier.name);
      path.remove();
    } else if (t.isExpression(declaration) || !declaration.id) {
      // Declare a variable to hold the exported value.
      path.replaceWith(t.variableDeclaration('var', [t.variableDeclarator(identifier, t.toExpression(declaration))]));
      path.scope.registerDeclaration(path);
    } else {
      // Rename the declaration to the exported name.
      safeRename(path, asset, declaration.id.name, identifier.name);
      path.replaceWith(declaration);
    }

    if (!asset.cacheData.exports['default']) {
      asset.cacheData.exports['default'] = identifier.name;
    } // Mark the asset as an ES6 module, so we handle imports correctly in the packager.


    asset.cacheData.isES6Module = true;
  },

  ExportNamedDeclaration(path, asset) {
    let _path$node3 = path.node,
        declaration = _path$node3.declaration,
        source = _path$node3.source,
        specifiers = _path$node3.specifiers;

    if (source) {
      var _iteratorNormalCompletion2 = true;
      var _didIteratorError2 = false;
      var _iteratorError2 = undefined;

      try {
        for (var _iterator2 = specifiers[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
          let specifier = _step2.value;
          let exported = specifier.exported;

          if (t.isExportDefaultSpecifier(specifier)) {
            asset.cacheData.exports[exported.name] = [source.value, 'default'];
          } else if (t.isExportNamespaceSpecifier(specifier)) {
            asset.cacheData.exports[exported.name] = [source.value, '*'];
          } else if (t.isExportSpecifier(specifier)) {
            asset.cacheData.exports[exported.name] = [source.value, specifier.local.name];
          }

          let id = getIdentifier(asset, 'import', exported.name);
          asset.cacheData.imports[id.name] = asset.cacheData.exports[exported.name];
          path.insertAfter(EXPORT_ASSIGN_TEMPLATE({
            EXPORTS: getExportsIdentifier(asset, path.scope),
            NAME: exported,
            LOCAL: id
          }));
        }
      } catch (err) {
        _didIteratorError2 = true;
        _iteratorError2 = err;
      } finally {
        try {
          if (!_iteratorNormalCompletion2 && _iterator2.return != null) {
            _iterator2.return();
          }
        } finally {
          if (_didIteratorError2) {
            throw _iteratorError2;
          }
        }
      }

      addImport(asset, path);
      path.remove();
    } else if (declaration) {
      path.replaceWith(declaration);
      let identifiers = t.isIdentifier(declaration.id) ? [declaration.id] : t.getBindingIdentifiers(declaration);

      for (let id in identifiers) {
        addExport(asset, path, identifiers[id], identifiers[id]);
      }
    } else if (specifiers.length > 0) {
      var _iteratorNormalCompletion3 = true;
      var _didIteratorError3 = false;
      var _iteratorError3 = undefined;

      try {
        for (var _iterator3 = specifiers[Symbol.iterator](), _step3; !(_iteratorNormalCompletion3 = (_step3 = _iterator3.next()).done); _iteratorNormalCompletion3 = true) {
          let specifier = _step3.value;
          addExport(asset, path, specifier.local, specifier.exported);
        }
      } catch (err) {
        _didIteratorError3 = true;
        _iteratorError3 = err;
      } finally {
        try {
          if (!_iteratorNormalCompletion3 && _iterator3.return != null) {
            _iterator3.return();
          }
        } finally {
          if (_didIteratorError3) {
            throw _iteratorError3;
          }
        }
      }

      path.remove();
    } // Mark the asset as an ES6 module, so we handle imports correctly in the packager.


    asset.cacheData.isES6Module = true;
  },

  ExportAllDeclaration(path, asset) {
    asset.cacheData.wildcards.push(path.node.source.value);
    asset.cacheData.isES6Module = true;
    path.replaceWith(EXPORT_ALL_TEMPLATE({
      OLD_NAME: getExportsIdentifier(asset),
      SOURCE: t.stringLiteral(path.node.source.value),
      ID: t.stringLiteral(asset.id)
    }));
  }

};

function addImport(asset, path) {
  // Replace with a $parcel$require call so we know where to insert side effects.
  let requireCall = REQUIRE_CALL_TEMPLATE({
    ID: t.stringLiteral(asset.id),
    SOURCE: t.stringLiteral(path.node.source.value)
  }); // Hoist the call to the top of the file.

  let lastImport = path.scope.getData('hoistedImport');

  if (lastImport) {
    var _lastImport$insertAft = lastImport.insertAfter(requireCall);

    var _lastImport$insertAft2 = (0, _slicedToArray2.default)(_lastImport$insertAft, 1);

    lastImport = _lastImport$insertAft2[0];
  } else {
    var _path$parentPath$unsh = path.parentPath.unshiftContainer('body', [requireCall]);

    var _path$parentPath$unsh2 = (0, _slicedToArray2.default)(_path$parentPath$unsh, 1);

    lastImport = _path$parentPath$unsh2[0];
  }

  path.scope.setData('hoistedImport', lastImport);
}

function addExport(asset, path, local, exported) {
  let scope = path.scope.getProgramParent();
  let identifier = getExportIdentifier(asset, exported.name);

  if (asset.cacheData.imports[local.name]) {
    asset.cacheData.exports[exported.name] = asset.cacheData.imports[local.name];
    identifier = t.identifier(local.name);
  }

  if (hasExport(asset, local.name)) {
    identifier = t.identifier(local.name);
  }

  let assignNode = EXPORT_ASSIGN_TEMPLATE({
    EXPORTS: getExportsIdentifier(asset, scope),
    NAME: t.identifier(exported.name),
    LOCAL: identifier
  });
  let binding = scope.getBinding(local.name);
  let constantViolations = binding ? binding.constantViolations.concat(path) : [path];

  if (!asset.cacheData.exports[exported.name]) {
    asset.cacheData.exports[exported.name] = identifier.name;
  }

  try {
    rename(scope, local.name, identifier.name);
  } catch (e) {
    throw new Error('export ' + e.message);
  }

  constantViolations.forEach(path => path.insertAfter(t.cloneDeep(assignNode)));
}

function hasExport(asset, name) {
  let exports = asset.cacheData.exports;
  return Object.keys(exports).some(k => exports[k] === name);
}

function safeRename(path, asset, from, to) {
  if (from === to) {
    return;
  } // If the binding that we're renaming is constant, it's safe to rename it.
  // Otherwise, create a new binding that references the original.


  let binding = path.scope.getBinding(from);

  if (binding && binding.constant) {
    rename(path.scope, from, to);
  } else {
    let _path$insertAfter = path.insertAfter(t.variableDeclaration('var', [t.variableDeclarator(t.identifier(to), t.identifier(from))])),
        _path$insertAfter2 = (0, _slicedToArray2.default)(_path$insertAfter, 1),
        decl = _path$insertAfter2[0];

    path.scope.getBinding(from).reference(decl.get('declarations.0.init'));
    path.scope.registerDeclaration(decl);
  }
}

function getExportsIdentifier(asset, scope) {
  if (scope && scope.getData('shouldWrap')) {
    return t.identifier('exports');
  } else {
    return getIdentifier(asset, 'exports');
  }
}