blockly/generators/javascript.js

/**
 * @license
 * Copyright 2012 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @fileoverview Helper functions for generating JavaScript for blocks.
 * @suppress {checkTypes|globalThis}
 */
'use strict';

goog.module('Blockly.JavaScript');
goog.module.declareLegacyNamespace();

const Variables = goog.require('Blockly.Variables');
const objectUtils = goog.require('Blockly.utils.object');
const stringUtils = goog.require('Blockly.utils.string');
const {Block} = goog.requireType('Blockly.Block');
const {Generator} = goog.require('Blockly.Generator');
const {globalThis} = goog.require('Blockly.utils.global');
const {inputTypes} = goog.require('Blockly.inputTypes');
const {Names, NameType} = goog.require('Blockly.Names');
const {Workspace} = goog.requireType('Blockly.Workspace');


/**
 * JavaScript code generator.
 * @type {!Generator}
 */
const JavaScript = new Generator('JavaScript');

/**
 * List of illegal variable names.
 * This is not intended to be a security feature.  Blockly is 100% client-side,
 * so bypassing this list is trivial.  This is intended to prevent users from
 * accidentally clobbering a built-in object or function.
 * @private
 */
JavaScript.addReservedWords(
    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Lexical_grammar#Keywords
    'break,case,catch,class,const,continue,debugger,default,delete,do,else,export,extends,finally,for,function,if,import,in,instanceof,new,return,super,switch,this,throw,try,typeof,var,void,while,with,yield,' +
    'enum,' +
    'implements,interface,let,package,private,protected,public,static,' +
    'await,' +
    'null,true,false,' +
    // Magic variable.
    'arguments,' +
    // Everything in the current environment (835 items in Chrome, 104 in Node).
    Object.getOwnPropertyNames(globalThis).join(','));

/**
 * Order of operation ENUMs.
 * https://developer.mozilla.org/en/JavaScript/Reference/Operators/Operator_Precedence
 */
JavaScript.ORDER_ATOMIC = 0;            // 0 "" ...
JavaScript.ORDER_NEW = 1.1;             // new
JavaScript.ORDER_MEMBER = 1.2;          // . []
JavaScript.ORDER_FUNCTION_CALL = 2;     // ()
JavaScript.ORDER_INCREMENT = 3;         // ++
JavaScript.ORDER_DECREMENT = 3;         // --
JavaScript.ORDER_BITWISE_NOT = 4.1;     // ~
JavaScript.ORDER_UNARY_PLUS = 4.2;      // +
JavaScript.ORDER_UNARY_NEGATION = 4.3;  // -
JavaScript.ORDER_LOGICAL_NOT = 4.4;     // !
JavaScript.ORDER_TYPEOF = 4.5;          // typeof
JavaScript.ORDER_VOID = 4.6;            // void
JavaScript.ORDER_DELETE = 4.7;          // delete
JavaScript.ORDER_AWAIT = 4.8;           // await
JavaScript.ORDER_EXPONENTIATION = 5.0;  // **
JavaScript.ORDER_MULTIPLICATION = 5.1;  // *
JavaScript.ORDER_DIVISION = 5.2;        // /
JavaScript.ORDER_MODULUS = 5.3;         // %
JavaScript.ORDER_SUBTRACTION = 6.1;     // -
JavaScript.ORDER_ADDITION = 6.2;        // +
JavaScript.ORDER_BITWISE_SHIFT = 7;     // << >> >>>
JavaScript.ORDER_RELATIONAL = 8;        // < <= > >=
JavaScript.ORDER_IN = 8;                // in
JavaScript.ORDER_INSTANCEOF = 8;        // instanceof
JavaScript.ORDER_EQUALITY = 9;          // == != === !==
JavaScript.ORDER_BITWISE_AND = 10;      // &
JavaScript.ORDER_BITWISE_XOR = 11;      // ^
JavaScript.ORDER_BITWISE_OR = 12;       // |
JavaScript.ORDER_LOGICAL_AND = 13;      // &&
JavaScript.ORDER_LOGICAL_OR = 14;       // ||
JavaScript.ORDER_CONDITIONAL = 15;      // ?:
JavaScript.ORDER_ASSIGNMENT = 16;       // = += -= **= *= /= %= <<= >>= ...
JavaScript.ORDER_YIELD = 17;            // yield
JavaScript.ORDER_COMMA = 18;            // ,
JavaScript.ORDER_NONE = 99;             // (...)

/**
 * List of outer-inner pairings that do NOT require parentheses.
 * @type {!Array<!Array<number>>}
 */
JavaScript.ORDER_OVERRIDES = [
  // (foo()).bar -> foo().bar
  // (foo())[0] -> foo()[0]
  [JavaScript.ORDER_FUNCTION_CALL, JavaScript.ORDER_MEMBER],
  // (foo())() -> foo()()
  [JavaScript.ORDER_FUNCTION_CALL, JavaScript.ORDER_FUNCTION_CALL],
  // (foo.bar).baz -> foo.bar.baz
  // (foo.bar)[0] -> foo.bar[0]
  // (foo[0]).bar -> foo[0].bar
  // (foo[0])[1] -> foo[0][1]
  [JavaScript.ORDER_MEMBER, JavaScript.ORDER_MEMBER],
  // (foo.bar)() -> foo.bar()
  // (foo[0])() -> foo[0]()
  [JavaScript.ORDER_MEMBER, JavaScript.ORDER_FUNCTION_CALL],

  // !(!foo) -> !!foo
  [JavaScript.ORDER_LOGICAL_NOT, JavaScript.ORDER_LOGICAL_NOT],
  // a * (b * c) -> a * b * c
  [JavaScript.ORDER_MULTIPLICATION, JavaScript.ORDER_MULTIPLICATION],
  // a + (b + c) -> a + b + c
  [JavaScript.ORDER_ADDITION, JavaScript.ORDER_ADDITION],
  // a && (b && c) -> a && b && c
  [JavaScript.ORDER_LOGICAL_AND, JavaScript.ORDER_LOGICAL_AND],
  // a || (b || c) -> a || b || c
  [JavaScript.ORDER_LOGICAL_OR, JavaScript.ORDER_LOGICAL_OR]
];

/**
 * Whether the init method has been called.
 * @type {?boolean}
 */
JavaScript.isInitialized = false;

/**
 * Initialise the database of variable names.
 * @param {!Workspace} workspace Workspace to generate code from.
 */
JavaScript.init = function(workspace) {
  // Call Blockly.Generator's init.
  Object.getPrototypeOf(this).init.call(this);

  if (!this.nameDB_) {
    this.nameDB_ = new Names(this.RESERVED_WORDS_);
  } else {
    this.nameDB_.reset();
  }

  this.nameDB_.setVariableMap(workspace.getVariableMap());
  this.nameDB_.populateVariables(workspace);
  this.nameDB_.populateProcedures(workspace);

  const defvars = [];
  // Add developer variables (not created or named by the user).
  const devVarList = Variables.allDeveloperVariables(workspace);
  for (let i = 0; i < devVarList.length; i++) {
    defvars.push(
        this.nameDB_.getName(devVarList[i], NameType.DEVELOPER_VARIABLE));
  }

  // Add user variables, but only ones that are being used.
  const variables = Variables.allUsedVarModels(workspace);
  for (let i = 0; i < variables.length; i++) {
    defvars.push(this.nameDB_.getName(variables[i].getId(), NameType.VARIABLE));
  }

  // Declare all of the variables.
  if (defvars.length) {
    this.definitions_['variables'] = 'var ' + defvars.join(', ') + ';';
  }
  this.isInitialized = true;
};

/**
 * Prepend the generated code with the variable definitions.
 * @param {string} code Generated code.
 * @return {string} Completed code.
 */
JavaScript.finish = function(code) {
  // Convert the definitions dictionary into a list.
  const definitions = objectUtils.values(this.definitions_);
  // Call Blockly.Generator's finish.
  code = Object.getPrototypeOf(this).finish.call(this, code);
  this.isInitialized = false;

  this.nameDB_.reset();
  return definitions.join('\n\n') + '\n\n\n' + code;
};

/**
 * Naked values are top-level blocks with outputs that aren't plugged into
 * anything.  A trailing semicolon is needed to make this legal.
 * @param {string} line Line of generated code.
 * @return {string} Legal line of code.
 */
JavaScript.scrubNakedValue = function(line) {
  return line + ';\n';
};

/**
 * Encode a string as a properly escaped JavaScript string, complete with
 * quotes.
 * @param {string} string Text to encode.
 * @return {string} JavaScript string.
 * @protected
 */
JavaScript.quote_ = function(string) {
  // Can't use goog.string.quote since Google's style guide recommends
  // JS string literals use single quotes.
  string = string.replace(/\\/g, '\\\\')
               .replace(/\n/g, '\\\n')
               .replace(/'/g, '\\\'');
  return '\'' + string + '\'';
};

/**
 * Encode a string as a properly escaped multiline JavaScript string, complete
 * with quotes.
 * @param {string} string Text to encode.
 * @return {string} JavaScript string.
 * @protected
 */
JavaScript.multiline_quote_ = function(string) {
  // Can't use goog.string.quote since Google's style guide recommends
  // JS string literals use single quotes.
  const lines = string.split(/\n/g).map(this.quote_);
  return lines.join(' + \'\\n\' +\n');
};

/**
 * Common tasks for generating JavaScript from blocks.
 * Handles comments for the specified block and any connected value blocks.
 * Calls any statements following this block.
 * @param {!Block} block The current block.
 * @param {string} code The JavaScript code created for this block.
 * @param {boolean=} opt_thisOnly True to generate code for only this statement.
 * @return {string} JavaScript code with comments and subsequent blocks added.
 * @protected
 */
JavaScript.scrub_ = function(block, code, opt_thisOnly) {
  let commentCode = '';
  // Only collect comments for blocks that aren't inline.
  if (!block.outputConnection || !block.outputConnection.targetConnection) {
    // Collect comment for this block.
    let comment = block.getCommentText();
    if (comment) {
      comment = stringUtils.wrap(comment, this.COMMENT_WRAP - 3);
      commentCode += this.prefixLines(comment + '\n', '// ');
    }
    // Collect comments for all value arguments.
    // Don't collect comments for nested statements.
    for (let i = 0; i < block.inputList.length; i++) {
      if (block.inputList[i].type === inputTypes.VALUE) {
        const childBlock = block.inputList[i].connection.targetBlock();
        if (childBlock) {
          comment = this.allNestedComments(childBlock);
          if (comment) {
            commentCode += this.prefixLines(comment, '// ');
          }
        }
      }
    }
  }
  const nextBlock = block.nextConnection && block.nextConnection.targetBlock();
  const nextCode = opt_thisOnly ? '' : this.blockToCode(nextBlock);
  return commentCode + code + nextCode;
};

/**
 * Gets a property and adjusts the value while taking into account indexing.
 * @param {!Block} block The block.
 * @param {string} atId The property ID of the element to get.
 * @param {number=} opt_delta Value to add.
 * @param {boolean=} opt_negate Whether to negate the value.
 * @param {number=} opt_order The highest order acting on this value.
 * @return {string|number}
 */
JavaScript.getAdjusted = function(
    block, atId, opt_delta, opt_negate, opt_order) {
  let delta = opt_delta || 0;
  let order = opt_order || this.ORDER_NONE;
  if (block.workspace.options.oneBasedIndex) {
    delta--;
  }
  const defaultAtIndex = block.workspace.options.oneBasedIndex ? '1' : '0';

  let innerOrder;
  let outerOrder = order;
  if (delta > 0) {
    outerOrder = this.ORDER_ADDITION;
    innerOrder = this.ORDER_ADDITION;
  } else if (delta < 0) {
    outerOrder = this.ORDER_SUBTRACTION;
    innerOrder = this.ORDER_SUBTRACTION;
  } else if (opt_negate) {
    outerOrder = this.ORDER_UNARY_NEGATION;
    innerOrder = this.ORDER_UNARY_NEGATION;
  }

  let at = this.valueToCode(block, atId, outerOrder) || defaultAtIndex;

  if (stringUtils.isNumber(at)) {
    // If the index is a naked number, adjust it right now.
    at = Number(at) + delta;
    if (opt_negate) {
      at = -at;
    }
  } else {
    // If the index is dynamic, adjust it in code.
    if (delta > 0) {
      at = at + ' + ' + delta;
    } else if (delta < 0) {
      at = at + ' - ' + -delta;
    }
    if (opt_negate) {
      if (delta) {
        at = '-(' + at + ')';
      } else {
        at = '-' + at;
      }
    }
    innerOrder = Math.floor(innerOrder);
    order = Math.floor(order);
    if (innerOrder && order >= innerOrder) {
      at = '(' + at + ')';
    }
  }
  return at;
};

exports = JavaScript;