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blockly/generators/javascript/math.js

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JavaScript

/**
* @license
* Copyright 2012 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Generating JavaScript for math blocks.
* @suppress {missingRequire}
*/
'use strict';
goog.module('Blockly.JavaScript.math');
const JavaScript = goog.require('Blockly.JavaScript');
const {NameType} = goog.require('Blockly.Names');
JavaScript['math_number'] = function(block) {
// Numeric value.
const code = Number(block.getFieldValue('NUM'));
const order = code >= 0 ? JavaScript.ORDER_ATOMIC :
JavaScript.ORDER_UNARY_NEGATION;
return [code, order];
};
JavaScript['math_arithmetic'] = function(block) {
// Basic arithmetic operators, and power.
const OPERATORS = {
'ADD': [' + ', JavaScript.ORDER_ADDITION],
'MINUS': [' - ', JavaScript.ORDER_SUBTRACTION],
'MULTIPLY': [' * ', JavaScript.ORDER_MULTIPLICATION],
'DIVIDE': [' / ', JavaScript.ORDER_DIVISION],
'POWER': [null, JavaScript.ORDER_NONE], // Handle power separately.
};
const tuple = OPERATORS[block.getFieldValue('OP')];
const operator = tuple[0];
const order = tuple[1];
const argument0 = JavaScript.valueToCode(block, 'A', order) || '0';
const argument1 = JavaScript.valueToCode(block, 'B', order) || '0';
let code;
// Power in JavaScript requires a special case since it has no operator.
if (!operator) {
code = 'Math.pow(' + argument0 + ', ' + argument1 + ')';
return [code, JavaScript.ORDER_FUNCTION_CALL];
}
code = argument0 + operator + argument1;
return [code, order];
};
JavaScript['math_single'] = function(block) {
// Math operators with single operand.
const operator = block.getFieldValue('OP');
let code;
let arg;
if (operator === 'NEG') {
// Negation is a special case given its different operator precedence.
arg = JavaScript.valueToCode(block, 'NUM',
JavaScript.ORDER_UNARY_NEGATION) || '0';
if (arg[0] === '-') {
// --3 is not legal in JS.
arg = ' ' + arg;
}
code = '-' + arg;
return [code, JavaScript.ORDER_UNARY_NEGATION];
}
if (operator === 'SIN' || operator === 'COS' || operator === 'TAN') {
arg = JavaScript.valueToCode(block, 'NUM',
JavaScript.ORDER_DIVISION) || '0';
} else {
arg = JavaScript.valueToCode(block, 'NUM',
JavaScript.ORDER_NONE) || '0';
}
// First, handle cases which generate values that don't need parentheses
// wrapping the code.
switch (operator) {
case 'ABS':
code = 'Math.abs(' + arg + ')';
break;
case 'ROOT':
code = 'Math.sqrt(' + arg + ')';
break;
case 'LN':
code = 'Math.log(' + arg + ')';
break;
case 'EXP':
code = 'Math.exp(' + arg + ')';
break;
case 'POW10':
code = 'Math.pow(10,' + arg + ')';
break;
case 'ROUND':
code = 'Math.round(' + arg + ')';
break;
case 'ROUNDUP':
code = 'Math.ceil(' + arg + ')';
break;
case 'ROUNDDOWN':
code = 'Math.floor(' + arg + ')';
break;
case 'SIN':
code = 'Math.sin(' + arg + ' / 180 * Math.PI)';
break;
case 'COS':
code = 'Math.cos(' + arg + ' / 180 * Math.PI)';
break;
case 'TAN':
code = 'Math.tan(' + arg + ' / 180 * Math.PI)';
break;
}
if (code) {
return [code, JavaScript.ORDER_FUNCTION_CALL];
}
// Second, handle cases which generate values that may need parentheses
// wrapping the code.
switch (operator) {
case 'LOG10':
code = 'Math.log(' + arg + ') / Math.log(10)';
break;
case 'ASIN':
code = 'Math.asin(' + arg + ') / Math.PI * 180';
break;
case 'ACOS':
code = 'Math.acos(' + arg + ') / Math.PI * 180';
break;
case 'ATAN':
code = 'Math.atan(' + arg + ') / Math.PI * 180';
break;
default:
throw Error('Unknown math operator: ' + operator);
}
return [code, JavaScript.ORDER_DIVISION];
};
JavaScript['math_constant'] = function(block) {
// Constants: PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2), INFINITY.
const CONSTANTS = {
'PI': ['Math.PI', JavaScript.ORDER_MEMBER],
'E': ['Math.E', JavaScript.ORDER_MEMBER],
'GOLDEN_RATIO': ['(1 + Math.sqrt(5)) / 2', JavaScript.ORDER_DIVISION],
'SQRT2': ['Math.SQRT2', JavaScript.ORDER_MEMBER],
'SQRT1_2': ['Math.SQRT1_2', JavaScript.ORDER_MEMBER],
'INFINITY': ['Infinity', JavaScript.ORDER_ATOMIC],
};
return CONSTANTS[block.getFieldValue('CONSTANT')];
};
JavaScript['math_number_property'] = function(block) {
// Check if a number is even, odd, prime, whole, positive, or negative
// or if it is divisible by certain number. Returns true or false.
const PROPERTIES = {
'EVEN': [' % 2 === 0', JavaScript.ORDER_MODULUS, JavaScript.ORDER_EQUALITY],
'ODD': [' % 2 === 1', JavaScript.ORDER_MODULUS, JavaScript.ORDER_EQUALITY],
'WHOLE': [' % 1 === 0', JavaScript.ORDER_MODULUS,
JavaScript.ORDER_EQUALITY],
'POSITIVE': [' > 0', JavaScript.ORDER_RELATIONAL,
JavaScript.ORDER_RELATIONAL],
'NEGATIVE': [' < 0', JavaScript.ORDER_RELATIONAL,
JavaScript.ORDER_RELATIONAL],
'DIVISIBLE_BY': [null, JavaScript.ORDER_MODULUS, JavaScript.ORDER_EQUALITY],
'PRIME': [null, JavaScript.ORDER_NONE, JavaScript.ORDER_FUNCTION_CALL],
};
const dropdownProperty = block.getFieldValue('PROPERTY');
const [suffix, inputOrder, outputOrder] = PROPERTIES[dropdownProperty];
const numberToCheck = JavaScript.valueToCode(block, 'NUMBER_TO_CHECK',
inputOrder) || '0';
let code;
if (dropdownProperty === 'PRIME') {
// Prime is a special case as it is not a one-liner test.
const functionName = JavaScript.provideFunction_('mathIsPrime', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(n) {
// https://en.wikipedia.org/wiki/Primality_test#Naive_methods
if (n == 2 || n == 3) {
return true;
}
// False if n is NaN, negative, is 1, or not whole.
// And false if n is divisible by 2 or 3.
if (isNaN(n) || n <= 1 || n % 1 !== 0 || n % 2 === 0 || n % 3 === 0) {
return false;
}
// Check all the numbers of form 6k +/- 1, up to sqrt(n).
for (var x = 6; x <= Math.sqrt(n) + 1; x += 6) {
if (n % (x - 1) === 0 || n % (x + 1) === 0) {
return false;
}
}
return true;
}
`);
code = functionName + '(' + numberToCheck + ')';
} else if (dropdownProperty === 'DIVISIBLE_BY') {
const divisor = JavaScript.valueToCode(block, 'DIVISOR',
JavaScript.ORDER_MODULUS) || '0';
code = numberToCheck + ' % ' + divisor + ' === 0';
} else {
code = numberToCheck + suffix;
}
return [code, outputOrder];
};
JavaScript['math_change'] = function(block) {
// Add to a variable in place.
const argument0 = JavaScript.valueToCode(block, 'DELTA',
JavaScript.ORDER_ADDITION) || '0';
const varName = JavaScript.nameDB_.getName(
block.getFieldValue('VAR'), NameType.VARIABLE);
return varName + ' = (typeof ' + varName + ' === \'number\' ? ' + varName +
' : 0) + ' + argument0 + ';\n';
};
// Rounding functions have a single operand.
JavaScript['math_round'] = JavaScript['math_single'];
// Trigonometry functions have a single operand.
JavaScript['math_trig'] = JavaScript['math_single'];
JavaScript['math_on_list'] = function(block) {
// Math functions for lists.
const func = block.getFieldValue('OP');
let list;
let code;
switch (func) {
case 'SUM':
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_MEMBER) || '[]';
code = list + '.reduce(function(x, y) {return x + y;}, 0)';
break;
case 'MIN':
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = 'Math.min.apply(null, ' + list + ')';
break;
case 'MAX':
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = 'Math.max.apply(null, ' + list + ')';
break;
case 'AVERAGE': {
// mathMean([null,null,1,3]) === 2.0.
const functionName = JavaScript.provideFunction_('mathMean', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(myList) {
return myList.reduce(function(x, y) {return x + y;}, 0) / myList.length;
}
`);
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = functionName + '(' + list + ')';
break;
}
case 'MEDIAN': {
// mathMedian([null,null,1,3]) === 2.0.
const functionName = JavaScript.provideFunction_('mathMedian', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(myList) {
var localList = myList.filter(function (x) {return typeof x === 'number';});
if (!localList.length) return null;
localList.sort(function(a, b) {return b - a;});
if (localList.length % 2 === 0) {
return (localList[localList.length / 2 - 1] + localList[localList.length / 2]) / 2;
} else {
return localList[(localList.length - 1) / 2];
}
}
`);
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = functionName + '(' + list + ')';
break;
}
case 'MODE': {
// As a list of numbers can contain more than one mode,
// the returned result is provided as an array.
// Mode of [3, 'x', 'x', 1, 1, 2, '3'] -> ['x', 1].
const functionName = JavaScript.provideFunction_('mathModes', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(values) {
var modes = [];
var counts = [];
var maxCount = 0;
for (var i = 0; i < values.length; i++) {
var value = values[i];
var found = false;
var thisCount;
for (var j = 0; j < counts.length; j++) {
if (counts[j][0] === value) {
thisCount = ++counts[j][1];
found = true;
break;
}
}
if (!found) {
counts.push([value, 1]);
thisCount = 1;
}
maxCount = Math.max(thisCount, maxCount);
}
for (var j = 0; j < counts.length; j++) {
if (counts[j][1] === maxCount) {
modes.push(counts[j][0]);
}
}
return modes;
}
`);
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = functionName + '(' + list + ')';
break;
}
case 'STD_DEV': {
const functionName = JavaScript.provideFunction_('mathStandardDeviation', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(numbers) {
var n = numbers.length;
if (!n) return null;
var mean = numbers.reduce(function(x, y) {return x + y;}) / n;
var variance = 0;
for (var j = 0; j < n; j++) {
variance += Math.pow(numbers[j] - mean, 2);
}
variance = variance / n;
return Math.sqrt(variance);
}
`);
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = functionName + '(' + list + ')';
break;
}
case 'RANDOM': {
const functionName = JavaScript.provideFunction_('mathRandomList', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(list) {
var x = Math.floor(Math.random() * list.length);
return list[x];
}
`);
list = JavaScript.valueToCode(block, 'LIST',
JavaScript.ORDER_NONE) || '[]';
code = functionName + '(' + list + ')';
break;
}
default:
throw Error('Unknown operator: ' + func);
}
return [code, JavaScript.ORDER_FUNCTION_CALL];
};
JavaScript['math_modulo'] = function(block) {
// Remainder computation.
const argument0 = JavaScript.valueToCode(block, 'DIVIDEND',
JavaScript.ORDER_MODULUS) || '0';
const argument1 = JavaScript.valueToCode(block, 'DIVISOR',
JavaScript.ORDER_MODULUS) || '0';
const code = argument0 + ' % ' + argument1;
return [code, JavaScript.ORDER_MODULUS];
};
JavaScript['math_constrain'] = function(block) {
// Constrain a number between two limits.
const argument0 = JavaScript.valueToCode(block, 'VALUE',
JavaScript.ORDER_NONE) || '0';
const argument1 = JavaScript.valueToCode(block, 'LOW',
JavaScript.ORDER_NONE) || '0';
const argument2 = JavaScript.valueToCode(block, 'HIGH',
JavaScript.ORDER_NONE) || 'Infinity';
const code = 'Math.min(Math.max(' + argument0 + ', ' + argument1 + '), ' +
argument2 + ')';
return [code, JavaScript.ORDER_FUNCTION_CALL];
};
JavaScript['math_random_int'] = function(block) {
// Random integer between [X] and [Y].
const argument0 = JavaScript.valueToCode(block, 'FROM',
JavaScript.ORDER_NONE) || '0';
const argument1 = JavaScript.valueToCode(block, 'TO',
JavaScript.ORDER_NONE) || '0';
const functionName = JavaScript.provideFunction_('mathRandomInt', `
function ${JavaScript.FUNCTION_NAME_PLACEHOLDER_}(a, b) {
if (a > b) {
// Swap a and b to ensure a is smaller.
var c = a;
a = b;
b = c;
}
return Math.floor(Math.random() * (b - a + 1) + a);
}
`);
const code = functionName + '(' + argument0 + ', ' + argument1 + ')';
return [code, JavaScript.ORDER_FUNCTION_CALL];
};
JavaScript['math_random_float'] = function(block) {
// Random fraction between 0 and 1.
return ['Math.random()', JavaScript.ORDER_FUNCTION_CALL];
};
JavaScript['math_atan2'] = function(block) {
// Arctangent of point (X, Y) in degrees from -180 to 180.
const argument0 = JavaScript.valueToCode(block, 'X',
JavaScript.ORDER_NONE) || '0';
const argument1 = JavaScript.valueToCode(block, 'Y',
JavaScript.ORDER_NONE) || '0';
return ['Math.atan2(' + argument1 + ', ' + argument0 + ') / Math.PI * 180',
JavaScript.ORDER_DIVISION];
};