metro/packages/metro-babel7-plugin-react-transform/lib/index.js

/**
 * Copyright (c) 2004-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * In order to speed things up, we use transform caching. However, the project
 * codebase moves very fast and cache becomes invalid when some files change.
 *
 * CacheKey is used to generate a unique string that can be used as cache key.
 * The cache key consists of various dependency cache keys that change if the
 * output of the transform would change.
 *
 * Imported from https://github.com/gaearon/babel-plugin-react-transform
 * https://github.com/gaearon/babel-plugin-react-transform/commit/d7069df5c6f36a07857fd108067dc515b3a795ee
 *
 * @format
 * @noflow
 */

'use strict';

// temporary workaround, don't mind this package
/*eslint-disable eslint-comments/no-unlimited-disable*/
/*eslint-disable*/

const find = require('lodash/find');

const {addDefault} = require('@babel/helper-module-imports');

module.exports = {
  default: function({types: t, template}) {
    function matchesPatterns(path, patterns) {
      return !!find(patterns, pattern => {
        return (
          t.isIdentifier(path.node, {name: pattern}) ||
          path.matchesPattern(pattern)
        );
      });
    }

    function isReactLikeClass(node) {
      return !!find(node.body.body, classMember => {
        return (
          t.isClassMethod(classMember) &&
          t.isIdentifier(classMember.key, {name: 'render'})
        );
      });
    }

    function isReactLikeComponentObject(node) {
      return (
        t.isObjectExpression(node) &&
        !!find(node.properties, objectMember => {
          return (
            (t.isObjectProperty(objectMember) ||
              t.isObjectMethod(objectMember)) &&
            (t.isIdentifier(objectMember.key, {name: 'render'}) ||
              t.isStringLiteral(objectMember.key, {value: 'render'}))
          );
        })
      );
    }

    // `foo({ displayName: 'NAME' });` => 'NAME'
    function getDisplayName(node) {
      const property = find(
        node.arguments[0].properties,
        _node => _node.key.name === 'displayName',
      );
      return property && property.value.value;
    }

    function hasParentFunction(path) {
      return !!path.findParent(parentPath => parentPath.isFunction());
    }

    // wrapperFunction("componentId")(node)
    function wrapComponent(node, componentId, wrapperFunctionId) {
      return t.callExpression(
        t.callExpression(wrapperFunctionId, [t.stringLiteral(componentId)]),
        [node],
      );
    }

    // `{ name: foo }` => Node { type: "ObjectExpression", properties: [...] }
    function toObjectExpression(object) {
      const properties = Object.keys(object).map(key => {
        return t.objectProperty(t.identifier(key), object[key]);
      });

      return t.objectExpression(properties);
    }

    const wrapperFunctionTemplate = template(`
    function WRAPPER_FUNCTION_ID(ID_PARAM) {
      return function(COMPONENT_PARAM) {
        return EXPRESSION;
      };
    }
  `);

    const VISITED_KEY = 'react-transform-' + Date.now();

    const componentVisitor = {
      Class(path) {
        if (
          path.node[VISITED_KEY] ||
          !matchesPatterns(path.get('superClass'), this.superClasses) ||
          !isReactLikeClass(path.node)
        ) {
          return;
        }

        path.node[VISITED_KEY] = true;

        const componentName = (path.node.id && path.node.id.name) || null;
        const componentId =
          componentName || path.scope.generateUid('component');
        const isInFunction = hasParentFunction(path);

        this.components.push({
          id: componentId,
          name: componentName,
          isInFunction: isInFunction,
        });

        // Can't wrap ClassDeclarations
        const isStatement = t.isStatement(path.node);
        const isExport = t.isExportDefaultDeclaration(path.parent);

        if (isStatement && !isExport) {
          // class decl
          // need to work around Babel 7 detecting duplicate decls here

          path.insertAfter(
            t.expressionStatement(
              t.assignmentExpression(
                '=',
                t.identifier(componentId),
                wrapComponent(
                  t.identifier(componentId),
                  componentId,
                  this.wrapperFunctionId,
                ),
              ),
            ),
          );

          return;
        }

        const expression = t.toExpression(path.node);

        // wrapperFunction("componentId")(node)
        let wrapped = wrapComponent(
          expression,
          componentId,
          this.wrapperFunctionId,
        );
        let constId;

        if (isStatement) {
          // wrapperFunction("componentId")(class Foo ...) => const Foo = wrapperFunction("componentId")(class Foo ...)
          constId = t.identifier(componentName || componentId);
          wrapped = t.variableDeclaration('const', [
            t.variableDeclarator(constId, wrapped),
          ]);
        }

        if (isExport) {
          path.parentPath.insertBefore(wrapped);
          path.parent.declaration = constId;
        } else {
          path.replaceWith(wrapped);
        }
      },

      CallExpression(path) {
        if (
          path.node[VISITED_KEY] ||
          !matchesPatterns(path.get('callee'), this.factoryMethods) ||
          !isReactLikeComponentObject(path.node.arguments[0])
        ) {
          return;
        }

        path.node[VISITED_KEY] = true;

        // `foo({ displayName: 'NAME' });` => 'NAME'
        const componentName = getDisplayName(path.node);
        const componentId =
          componentName || path.scope.generateUid('component');
        const isInFunction = hasParentFunction(path);

        this.components.push({
          id: componentId,
          name: componentName,
          isInFunction: isInFunction,
        });

        path.replaceWith(
          wrapComponent(path.node, componentId, this.wrapperFunctionId),
        );
      },
    };

    class ReactTransformBuilder {
      constructor(file, options) {
        this.file = file;
        this.program = file.path;
        this.options = this.normalizeOptions(options);

        // @todo: clean this shit up
        this.configuredTransformsIds = [];
      }

      static validateOptions(options) {
        return typeof options === 'object' && Array.isArray(options.transforms);
      }

      static assertValidOptions(options) {
        if (!ReactTransformBuilder.validateOptions(options)) {
          throw new Error(
            'babel-plugin-react-transform requires that you specify options ' +
              'in .babelrc or from the Babel Node API, and that it is an object ' +
              'with a transforms property which is an array.',
          );
        }
      }

      normalizeOptions(options) {
        return {
          factoryMethods: options.factoryMethods || ['React.createClass'],
          superClasses: options.superClasses || [
            'React.Component',
            'React.PureComponent',
            'Component',
            'PureComponent',
          ],
          transforms: options.transforms.map(opts => {
            return {
              transform: opts.transform,
              locals: opts.locals || [],
              imports: opts.imports || [],
            };
          }),
        };
      }

      build(path) {
        const componentsDeclarationId = this.file.scope.generateUidIdentifier(
          'components',
        );
        const wrapperFunctionId = this.file.scope.generateUidIdentifier(
          'wrapComponent',
        );

        const components = this.collectAndWrapComponents(wrapperFunctionId);

        if (!components.length) {
          return;
        }

        const componentsDeclaration = this.initComponentsDeclaration(
          componentsDeclarationId,
          components,
        );
        const configuredTransforms = this.initTransformers(
          path,
          componentsDeclarationId,
        );
        const wrapperFunction = this.initWrapperFunction(wrapperFunctionId);

        const body = this.program.node.body;

        body.unshift(wrapperFunction);
        configuredTransforms.reverse().forEach(node => body.unshift(node));
        body.unshift(componentsDeclaration);
      }

      /**
       * const Foo = _wrapComponent('Foo')(class Foo extends React.Component {});
       * ...
       * const Bar = _wrapComponent('Bar')(React.createClass({
       *   displayName: 'Bar'
       * }));
       */
      collectAndWrapComponents(wrapperFunctionId) {
        const components = [];

        this.file.path.traverse(componentVisitor, {
          wrapperFunctionId: wrapperFunctionId,
          components: components,
          factoryMethods: this.options.factoryMethods,
          superClasses: this.options.superClasses,
          currentlyInFunction: false,
        });

        return components;
      }

      /**
       * const _components = {
       *   Foo: {
       *     displayName: "Foo"
       *   }
       * };
       */
      initComponentsDeclaration(componentsDeclarationId, components) {
        const props = components.map(component => {
          const componentId = component.id;
          const componentProps = [];

          if (component.name) {
            componentProps.push(
              t.objectProperty(
                t.identifier('displayName'),
                t.stringLiteral(component.name),
              ),
            );
          }

          if (component.isInFunction) {
            componentProps.push(
              t.objectProperty(
                t.identifier('isInFunction'),
                t.booleanLiteral(true),
              ),
            );
          }

          let objectKey;

          if (t.isValidIdentifier(componentId)) {
            objectKey = t.identifier(componentId);
          } else {
            objectKey = t.stringLiteral(componentId);
          }

          return t.objectProperty(
            objectKey,
            t.objectExpression(componentProps),
          );
        });

        return t.variableDeclaration('const', [
          t.variableDeclarator(
            componentsDeclarationId,
            t.objectExpression(props),
          ),
        ]);
      }

      /**
       * import _transformLib from "transform-lib";
       * ...
       * const _transformLib2 = _transformLib({
       *   filename: "filename",
       *   components: _components,
       *   locals: [],
       *   imports: []
       * });
       */
      initTransformers(path, componentsDeclarationId) {
        return this.options.transforms.map(transform => {
          const transformName = transform.transform;
          const transformImportId = addDefault(path, transformName, {
            nameHint: transformName,
          });

          const transformLocals = transform.locals.map(local => {
            return t.identifier(local);
          });

          const transformImports = transform.imports.map(importName => {
            return addDefault(path, importName, {hint: importName});
          });

          const configuredTransformId = this.file.scope.generateUidIdentifier(
            transformName,
          );
          const configuredTransform = t.variableDeclaration('const', [
            t.variableDeclarator(
              configuredTransformId,
              t.callExpression(transformImportId, [
                toObjectExpression({
                  filename: t.stringLiteral(
                    this.file.opts.filename || 'unknown',
                  ),
                  components: componentsDeclarationId,
                  locals: t.arrayExpression(transformLocals),
                  imports: t.arrayExpression(transformImports),
                }),
              ]),
            ),
          ]);

          this.configuredTransformsIds.push(configuredTransformId);

          return configuredTransform;
        });
      }

      /**
       * function _wrapComponent(id) {
       *   return function (Component) {
       *     return _transformLib2(Component, id);
       *   };
       * }
       */
      initWrapperFunction(wrapperFunctionId) {
        const idParam = t.identifier('id');
        const componentParam = t.identifier('Component');

        const expression = this.configuredTransformsIds
          .reverse()
          .reduce((memo, transformId) => {
            return t.callExpression(transformId, [memo, idParam]);
          }, componentParam);

        return wrapperFunctionTemplate({
          WRAPPER_FUNCTION_ID: wrapperFunctionId,
          ID_PARAM: idParam,
          COMPONENT_PARAM: componentParam,
          EXPRESSION: expression,
        });
      }
    }

    return {
      visitor: {
        Program(path, {file, opts}) {
          ReactTransformBuilder.assertValidOptions(opts);
          const builder = new ReactTransformBuilder(file, opts);
          builder.build(path);
        },
      },
    };
  },
};