simplify init

dist/helpers.js

@@ -152,6 +152,6 @@ var flatten = (function (_flatten) {
 
 exports.flatten = flatten;
 var removeSymbols = function removeSymbols(string) {
-  return string.replace(/\W/g, '');
+  return string.toString().replace(/\W/g, '');
 };
 exports.removeSymbols = removeSymbols;

dist/index.js

@@ -53,6 +53,7 @@ var Equation = {
 
     return stack;
   },
+
   /**
     * Creates an equation function which replaces variables
     * in the given expression with the values specified in order,
@@ -72,8 +73,7 @@ var Equation = {
     var variables = [];
 
     stack.forEach(function (a) {
-      if (typeof a === 'string' && !_.isNumber(a) && !_operators2['default'][a] && a === a.toLowerCase()) {
+      if (isVariable(a)) {
-        // grouped variables like (y) need to have their parantheses removed
         variables.push(_.removeSymbols(a));
       }
     });
@@ -95,6 +95,31 @@ var Equation = {
     };
   },
 
+  /**
+    * Simplifies a math expression
+    *
+    * Example:
+    *   2*x^2 + x - 2*x - x^2
+    *   becomes
+    *   x^2 - x
+    *
+    * @param {String} expression
+    *        The expression to create an equation for (containing variables)
+    * @return {String}
+    *         The simplified expression
+    */
+  simplify: function simplify(expression) {
+    var stack = parseExpression(expression);
+    stack = sortStack(stack);
+    stack = _.parseNumbers(stack);
+
+    console.dir(stack, {
+      depth: null
+    });
+
+    return expression;
+  },
+
   registerOperator: function registerOperator(key, options) {
     _operators2['default'][key] = options;
   },
@@ -177,6 +202,11 @@ var parseExpression = function parseExpression(expression) {
   return parseGroups(stack);
 };
 
+var isVariable = function isVariable(char) {
+  var ch = _.removeSymbols(char);
+  return typeof ch === 'string' && !_.isNumber(ch) && !_operators2['default'][ch] && char === ch.toLowerCase();
+};
+
 /**
   * Takes the parsed array from parseExpression and
   * groups up expressions in parantheses in deep arrays

dist/tests/basic.js

@@ -1,73 +0,0 @@
-'use strict';
-
-var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { 'default': obj }; };
-
-var _expect = require('chai');
-
-var _M = require('../index.js');
-
-var _M2 = _interopRequireWildcard(_M);
-
-describe('Basic math operators', function () {
-  it('should work for add +', function () {
-    _expect.expect(_M2['default'].solve('2+2')).to.equal(4);
-  });
-
-  it('should work for minus -', function () {
-    _expect.expect(_M2['default'].solve('15-3')).to.equal(12);
-  });
-
-  it('should work for divison /', function () {
-    _expect.expect(_M2['default'].solve('20/2')).to.equal(10);
-  });
-
-  it('should work for multiplication *', function () {
-    _expect.expect(_M2['default'].solve('6*3')).to.equal(18);
-  });
-
-  it('should work for power ^', function () {
-    _expect.expect(_M2['default'].solve('5^2')).to.equal(25);
-  });
-
-  it('should work for multi-digit numbers', function () {
-    _expect.expect(_M2['default'].solve('12+15')).to.equal(27);
-  });
-});
-
-describe('Precedence', function () {
-  it('Test case 1', function () {
-    _expect.expect(_M2['default'].solve('2+(2+1)*(1+1)^2')).to.equal(14);
-  });
-
-  it('Test case 2', function () {
-    _expect.expect(_M2['default'].solve('2+5*4/2-2')).to.equal(10);
-  });
-
-  it('Test case 3', function () {
-    _expect.expect(_M2['default'].solve('2+(5*4/2)-2')).to.equal(10);
-  });
-
-  it('Test case 4', function () {
-    _expect.expect(_M2['default'].solve('(2+2)^2+(5+1)*4+(2+(4/2)/2)')).to.equal(16 + 24 + 3);
-  });
-});
-
-describe('Functions', function () {
-  it('should work for with parantheses', function () {
-    _expect.expect(_M2['default'].solve('lg(4) * 5')).to.equal(10);
-  });
-
-  it('should work for without parantheses', function () {
-    _expect.expect(_M2['default'].solve('lg4 * 5')).to.equal(10);
-  });
-});
-
-describe('Constats', function () {
-  it('should work for constant values', function () {
-    _expect.expect(_M2['default'].solve('sin(PI/2)')).to.equal(1);
-  });
-
-  it('should work for functions as constants', function () {
-    _expect.expect(_M2['default'].solve('RAND')).to.not.equal(_M2['default'].solve('RAND'));
-  });
-});

dist/tests/simplify.js

@@ -0,0 +1,35 @@
+'use strict';
+
+var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { 'default': obj }; };
+
+var _expect = require('chai');
+
+var _M = require('../index.js');
+
+var _M2 = _interopRequireWildcard(_M);
+
+describe('Simplify simple math expressions', function () {
+  it('should work for add +', function () {
+    _expect.expect(_M2['default'].simplify('2+2-1')).to.equal('3');
+  });
+  //
+  // it('should work for minus -', () => {
+  //   expect(M.solve('15-3')).to.equal(12);
+  // });
+  //
+  // it('should work for divison /', () => {
+  //   expect(M.solve('20/2')).to.equal(10);
+  // });
+  //
+  // it('should work for multiplication *', () => {
+  //   expect(M.solve('6*3')).to.equal(18);
+  // });
+  //
+  // it('should work for power ^', () => {
+  //   expect(M.solve('5^2')).to.equal(25);
+  // });
+  //
+  // it('should work for multi-digit numbers', () => {
+  //   expect(M.solve('12+15')).to.equal(27);
+  // });
+});

lib/helpers.js

@@ -74,5 +74,5 @@ export const flatten = (arr) => {
 };
 
 export const removeSymbols = string => {
-  return string.replace(/\W/g, '');
+  return string.toString().replace(/\W/g, '');
 };

lib/index.js

@@ -30,6 +30,7 @@ let Equation = {
 
     return stack;
   },
+
   /**
     * Creates an equation function which replaces variables
     * in the given expression with the values specified in order,
@@ -49,9 +50,7 @@ let Equation = {
     let variables = [];
 
     stack.forEach(a => {
-      if (typeof a === 'string' && !_.isNumber(a) &&
+      if (isVariable(a)) {
-          !operators[a] && a === a.toLowerCase()) {
-        // grouped variables like (y) need to have their parantheses removed
         variables.push(_.removeSymbols(a));
       }
     });
@@ -69,6 +68,31 @@ let Equation = {
     };
   },
 
+  /**
+    * Simplifies a math expression
+    *
+    * Example:
+    *   2*x^2 + x - 2*x - x^2
+    *   becomes
+    *   x^2 - x
+    *
+    * @param {String} expression
+    *        The expression to create an equation for (containing variables)
+    * @return {String}
+    *         The simplified expression
+    */
+  simplify(expression) {
+    let stack = parseExpression(expression);
+    stack = sortStack(stack);
+    stack = _.parseNumbers(stack);
+
+    console.dir(stack, {
+      depth: null
+    });
+
+    return expression;
+  },
+
   registerOperator(key, options) {
     operators[key] = options;
   },
@@ -142,6 +166,12 @@ const parseExpression = expression => {
   return parseGroups(stack);
 };
 
+const isVariable = char => {
+  let ch = _.removeSymbols(char);
+  return typeof ch === 'string' && !_.isNumber(ch) &&
+         !operators[ch] && char === ch.toLowerCase();
+};
+
 /**
   * Takes the parsed array from parseExpression and
   * groups up expressions in parantheses in deep arrays

tests/simplify.js

@@ -0,0 +1,28 @@
+import {expect} from 'chai';
+import M from '../index.js';
+
+describe('Simplify simple math expressions', () => {
+  it('should work for add +', () => {
+    expect(M.simplify('2+2-1')).to.equal('3');
+  });
+  //
+  // it('should work for minus -', () => {
+  //   expect(M.solve('15-3')).to.equal(12);
+  // });
+  //
+  // it('should work for divison /', () => {
+  //   expect(M.solve('20/2')).to.equal(10);
+  // });
+  //
+  // it('should work for multiplication *', () => {
+  //   expect(M.solve('6*3')).to.equal(18);
+  // });
+  //
+  // it('should work for power ^', () => {
+  //   expect(M.solve('5^2')).to.equal(25);
+  // });
+  //
+  // it('should work for multi-digit numbers', () => {
+  //   expect(M.solve('12+15')).to.equal(27);
+  // });
+});