no-mixed-interpolation.js

/**
 * Copyright 2018 The AMP HTML Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const {
  assertAliases,
  definitionFile,
  singletonFunctions,
  transformableMethods,
} = require('../babel-plugins/log-module-metadata.js');

/**
 * @param {!Node} node
 * @return {boolean}
 */
function isBinaryConcat(node) {
  return node.type === 'BinaryExpression' && node.operator === '+';
}

/**
 * @param {!Node} node
 * @return {boolean}
 */
function hasTemplateLiteral(node) {
  if (node.type === 'TemplateLiteral') {
    return true;
  }

  // Allow for string concatenation operations.
  if (isBinaryConcat(node)) {
    return hasTemplateLiteral(node.left) && hasTemplateLiteral(node.right);
  }

  return false;
}

const selector = Object.keys(transformableMethods)
  .map((name) => `CallExpression[callee.property.name=${name}]`)
  .concat(assertAliases.map((name) => `CallExpression[callee.name=${name}]`))
  .join(',');

module.exports = {
  create(context) {
    return {
      [selector]: function (node) {
        // Don't evaluate or transform log.js
        if (context.getFilename().endsWith(definitionFile)) {
          return;
        }

        let methodInvokedName;

        const {callee} = node;

        // userAssert() and devAssert() aliases
        if (
          callee.type == 'Identifier' &&
          assertAliases.includes(callee.name)
        ) {
          methodInvokedName = 'assert';
        } else {
          // dev().assert() // enforce rule
          // dev.assert() // ignore
          const calleeObject = callee.object;
          if (!calleeObject || calleeObject.type !== 'CallExpression') {
            return;
          }

          // Make sure that the CallExpression is one of dev() or user().
          if (!singletonFunctions.includes(calleeObject.callee.name)) {
            return;
          }

          methodInvokedName = callee.property.name;
        }

        // Find the position of the argument we care about.
        const metadata = transformableMethods[methodInvokedName];

        // If there's no metadata, this is most likely a test file running
        // private methods on log.
        if (!metadata) {
          return;
        }

        const {variadic, messageArgPos} = metadata;
        // If method is not variadic we don't need to check.
        if (!variadic) {
          return;
        }

        const argToEval = node.arguments[messageArgPos];
        if (!argToEval) {
          return;
        }

        const errMsg = [
          'Mixing Template Strings and %s interpolation for log methods is',
          `not supported on ${methodInvokedName}. Please either use template`,
          'literals or use the log strformat(%s) style interpolation',
          'exclusively',
        ].join(' ');

        const hasVariadicInterpolation = node.arguments[metadata.startPos + 1];
        if (hasVariadicInterpolation && hasTemplateLiteral(argToEval)) {
          context.report({
            node: argToEval,
            message: errMsg,
          });
        }
      },
    };
  },
};