Merge branch 'gh-pages'

README.md

@@ -18,8 +18,10 @@ console.log(Equation.solve('4 * lg(4) ^ 3')); // 32
 
 // equation
 let sphereArea = Equation.equation('4 * PI * r^2');
-
 console.log(sphereArea(5)); // 314.1592653589793
+
+let test = Equation.equation('2x + 6y');
+console.log(test(4, 3)).to.equal(8 + 18);
 ```
 
 You can also register your own operators and constants.

dist/index.js

@@ -70,10 +70,14 @@ var Equation = {
     */
   equation: function equation(expression) {
     var stack = parseExpression(expression);
+    console.log(stack);
     var variables = [];
 
-    stack.forEach(function (a) {
+    stack.forEach(function varCheck(a) {
-      if (typeof a === 'string' && !_.isNumber(a) && !_operators2['default'][a] && a === a.toLowerCase()) {
+      if (Array.isArray(a)) {
+        return a.forEach(varCheck);
+      }
+      if (isVariable(a)) {
         // grouped variables like (y) need to have their parantheses removed
         variables.push(_.removeSymbols(a));
       }
@@ -84,15 +88,30 @@ var Equation = {
         args[_key] = arguments[_key];
       }
 
-      expression = expression.replace(/[a-z]*/g, function (a) {
+      stack.forEach(function varCheck(a, i, arr) {
+        if (Array.isArray(a)) {
+          return a.forEach(varCheck);
+        }
+
         var index = variables.indexOf(a);
         if (index > -1) {
-          return args[index] || 0;
+          // grouped variables like (y) need to have their parantheses removed
+          arr[i] = args[index];
         }
-        return a;
       });
 
-      return Equation.solve(expression);
+      stack = sortStack(stack);
+      stack = _.parseNumbers(stack);
+      stack = solveStack(stack);
+      // expression = expression.replace(/[a-z]*/g, a => {
+      //   let index = variables.indexOf(a);
+      //   if (index > -1) {
+      //     return args[index] || 0;
+      //   }
+      //   return a;
+      // });
+
+      return stack;
     };
   },
 
@@ -150,33 +169,50 @@ var MIN_PRECEDENCE = Math.min.apply(Math, _toConsumableArray(PRECEDENCES));
 var parseExpression = function parseExpression(expression) {
   var stream = new _ReadStream2['default'](expression),
       stack = [],
-      record = '';
+      record = '',
+      cur = undefined,
+      past = undefined;
 
   // Create an array of separated numbers & operators
   while (stream.next()) {
-    var cur = stream.current(),
+    cur = stream.current();
     past = stack.length - 1;
+
     if (cur === ' ') {
       continue;
     }
 
     // it's probably a function with a length more than one
-    if (!_.isNumber(cur) && !_operators2['default'][cur] && cur !== '.') {
+    if (!_.isNumber(cur) && !_operators2['default'][cur] && cur !== '.' && cur !== '(' && cur !== ')') {
+
       record += cur;
     } else if (record.length) {
+      var beforeRecord = past - (record.length - 1);
+      if (isVariable(record) && _.isNumber(stack[beforeRecord])) {
+        stack.push('*');
+      }
       stack.push(record, cur);
       record = '';
-    } else if (_.isNumber(stack[stack.length - 1]) && (_.isNumber(cur) || cur === '.')) {
 
-      stack[stack.length - 1] += cur;
+      // numbers and decimals
+    } else if (_.isNumber(stack[past]) && (_.isNumber(cur) || cur === '.')) {
+
+      stack[past] += cur;
+
+      // negation sign
     } else if (stack[past] === '-') {
-      var beforeSign = stack[stack.length - 2];
+      var beforeSign = stack[past - 1];
 
+      // 2 / -5 is OK, pass
       if (_operators2['default'][beforeSign]) {
         stack[past] += cur;
+
+        // (2+1) - 5 becomes (2+1) + -5
       } else if (beforeSign === ')') {
         stack[past] = '+';
         stack.push('-' + cur);
+
+        // 2 - 5 is also OK, pass
       } else if (_.isNumber(beforeSign)) {
         stack.push(cur);
       } else {
@@ -187,6 +223,10 @@ var parseExpression = function parseExpression(expression) {
     }
   }
   if (record.length) {
+    var beforeRecord = past - (record.length - 1);
+    if (isVariable(record) && _.isNumber(stack[beforeRecord])) {
+      stack.push('*');
+    }
     stack.push(record);
   }
 
@@ -353,7 +393,7 @@ var evaluate = function evaluate(stack) {
   var leftArguments = stack.slice(0, left),
       rightArguments = stack.slice(left + 1);
 
-  return (_operators$op = _operators2['default'][op]).fn.apply(_operators$op, _toConsumableArray(leftArguments).concat(_toConsumableArray(rightArguments)));
+  return fixFloat((_operators$op = _operators2['default'][op]).fn.apply(_operators$op, _toConsumableArray(leftArguments).concat(_toConsumableArray(rightArguments))));
 };
 
 /**
@@ -413,5 +453,28 @@ var replaceConstants = function replaceConstants(expression) {
   });
 };
 
+/**
+  * Fixes JavaScript's floating point precisions - Issue #5
+  *
+  * @param {Number} number
+  *        The number to fix
+  * @return {Number}
+  *         Fixed number
+  */
+var fixFloat = function fixFloat(number) {
+  return +number.toFixed(15);
+};
+
+/**
+  * Recognizes variables such as x, y, z
+  * @param {String} a
+  *        The string to check for
+  * @return {Boolean}
+  *         true if variable, else false
+  */
+var isVariable = function isVariable(a) {
+  return typeof a === 'string' && !_.isNumber(a) && !_operators2['default'][a] && a === a.toLowerCase();
+};
+
+exports.isVariable = isVariable;
 exports['default'] = Equation;
-module.exports = exports['default'];

dist/operators.js

@@ -109,6 +109,16 @@ exports['default'] = {
     fn: Math.cot,
     format: '10',
     precedence: -1
+  },
+  round: {
+    fn: Math.round,
+    format: '10',
+    precedence: -1
+  },
+  floor: {
+    fn: Math.floor,
+    format: '10',
+    precedence: -1
   }
 };
 module.exports = exports['default'];

dist/tests/equation.js

@@ -30,6 +30,11 @@ describe('Equations', function () {
     _expect.expect(equation).to['throw']();
   });
 
+  it('should work with NumVariable expressions like 2x', function () {
+    var equation = _M2['default'].equation('2x + 6y');
+    _expect.expect(equation(4, 3)).to.equal(8 + 18);
+  });
+
   it('Test case', function () {
     var equation = _M2['default'].equation('2+x*(y+4)+z^2');
     _expect.expect(equation(2, 4, 3)).to.equal(27);

dist/tests/solve.js

@@ -32,6 +32,13 @@ describe('Basic math operators', function () {
   it('should work for multi-digit numbers', function () {
     _expect.expect(_M2['default'].solve('12+15')).to.equal(27);
   });
+
+  it('should deal with floating precision of javascript - #5', function () {
+    _expect.expect(_M2['default'].solve('0.2 + 0.1')).to.equal(0.3);
+    _expect.expect(_M2['default'].solve('0.2 + 0.4')).to.equal(0.6);
+    _expect.expect(_M2['default'].solve('round(floor(1.23456789/0.2)) * 0.2')).to.equal(1.2);
+    _expect.expect(_M2['default'].solve('1.23456789 - (1.23456789 % 0.2)')).to.equal(1.2);
+  });
 });
 
 describe('Negative Numbers', function () {
@@ -67,11 +74,11 @@ describe('Precedence', function () {
 });
 
 describe('Functions', function () {
-  it('should work for with parantheses', function () {
+  it('should work with parantheses', function () {
     _expect.expect(_M2['default'].solve('lg(4) * 5')).to.equal(10);
   });
 
-  it('should work for without parantheses', function () {
+  it('should work without parantheses', function () {
     _expect.expect(_M2['default'].solve('lg4 * 5')).to.equal(10);
   });
 

lib/index.js

@@ -47,26 +47,44 @@ let Equation = {
     */
   equation(expression) {
     let stack = parseExpression(expression);
+    console.log(stack);
     let variables = [];
 
-    stack.forEach(a => {
+    stack.forEach(function varCheck(a) {
-      if (typeof a === 'string' && !_.isNumber(a) &&
+      if (Array.isArray(a)) {
-          !operators[a] && a === a.toLowerCase()) {
+        return a.forEach(varCheck);
+      }
+      if (isVariable(a)) {
         // grouped variables like (y) need to have their parantheses removed
         variables.push(_.removeSymbols(a));
       }
     });
 
     return function(...args) {
-      expression = expression.replace(/[a-z]*/g, a => {
+      stack.forEach(function varCheck(a, i, arr) {
+        if (Array.isArray(a)) {
+          return a.forEach(varCheck);
+        }
+
         let index = variables.indexOf(a);
         if (index > -1) {
-          return args[index] || 0;
+          // grouped variables like (y) need to have their parantheses removed
+          arr[i] = args[index];
         }
-        return a;
       });
 
-      return Equation.solve(expression);
+      stack = sortStack(stack);
+      stack = _.parseNumbers(stack);
+      stack = solveStack(stack);
+      // expression = expression.replace(/[a-z]*/g, a => {
+      //   let index = variables.indexOf(a);
+      //   if (index > -1) {
+      //     return args[index] || 0;
+      //   }
+      //   return a;
+      // });
+
+      return stack;
     };
   },
 
@@ -114,34 +132,51 @@ const MIN_PRECEDENCE = Math.min(...PRECEDENCES);
 const parseExpression = expression => {
   let stream = new ReadStream(expression),
       stack = [],
-      record = '';
+      record = '',
+      cur, past;
 
   // Create an array of separated numbers & operators
   while (stream.next()) {
-    const cur = stream.current(),
+    cur = stream.current();
     past = stack.length - 1;
+
     if (cur === ' ') {
       continue;
     }
 
     // it's probably a function with a length more than one
-    if (!_.isNumber(cur) && !operators[cur] && cur !== '.') {
+    if (!_.isNumber(cur) && !operators[cur] && cur !== '.' &&
+        cur !== '(' && cur !== ')') {
+
       record += cur;
     } else if (record.length) {
+      let beforeRecord = past - (record.length - 1);
+      if (isVariable(record) && _.isNumber(stack[beforeRecord])) {
+        stack.push('*');
+      }
       stack.push(record, cur);
       record = '';
-    } else if (_.isNumber(stack[stack.length - 1]) &&
+
+    // numbers and decimals
+    } else if (_.isNumber(stack[past]) &&
               (_.isNumber(cur) || cur === '.')) {
 
-      stack[stack.length - 1] += cur;
+      stack[past] += cur;
-    } else if (stack[past] === '-') {
-      const beforeSign = stack[stack.length - 2];
 
+      // negation sign
+    } else if (stack[past] === '-') {
+      const beforeSign = stack[past - 1];
+
+      // 2 / -5 is OK, pass
       if (operators[beforeSign]) {
         stack[past] += cur;
+
+        // (2+1) - 5 becomes (2+1) + -5
       } else if (beforeSign === ')') {
         stack[past] = '+';
         stack.push(`-${cur}`);
+
+        // 2 - 5 is also OK, pass
       } else if (_.isNumber(beforeSign)) {
         stack.push(cur);
       } else {
@@ -152,6 +187,10 @@ const parseExpression = expression => {
     }
   }
   if (record.length) {
+    let beforeRecord = past - (record.length - 1);
+    if (isVariable(record) && _.isNumber(stack[beforeRecord])) {
+      stack.push('*');
+    }
     stack.push(record);
   }
 
@@ -272,12 +311,13 @@ const evaluate = stack => {
   if (!op) {
     return stack[0];
   }
+
   const { left } = formatInfo(op);
 
   let leftArguments = stack.slice(0, left),
       rightArguments = stack.slice(left + 1);
 
-  return operators[op].fn(...leftArguments, ...rightArguments);
+  return fixFloat(operators[op].fn(...leftArguments, ...rightArguments));
 };
 
 /**
@@ -315,4 +355,28 @@ const replaceConstants = expression => {
   });
 };
 
+/**
+  * Fixes JavaScript's floating point precisions - Issue #5
+  *
+  * @param {Number} number
+  *        The number to fix
+  * @return {Number}
+  *         Fixed number
+  */
+const fixFloat = number => {
+  return +number.toFixed(15);
+};
+
+/**
+  * Recognizes variables such as x, y, z
+  * @param {String} a
+  *        The string to check for
+  * @return {Boolean}
+  *         true if variable, else false
+  */
+export const isVariable = a => {
+  return typeof a === 'string' && !_.isNumber(a) &&
+         !operators[a] && a === a.toLowerCase();
+};
+
 export default Equation;

lib/operators.js

@@ -88,5 +88,15 @@ export default {
     fn: Math.cot,
     format: '10',
     precedence: -1
+  },
+  'round': {
+    fn: Math.round,
+    format: '10',
+    precedence: -1
+  },
+  'floor': {
+    fn: Math.floor,
+    format: '10',
+    precedence: -1
   }
 };

tests/equation.js

@@ -23,6 +23,11 @@ describe('Equations', () => {
     expect(equation).to.throw();
   });
 
+  it('should work with NumVariable expressions like 2x', () => {
+    let equation = M.equation('2x + 6y');
+    expect(equation(4, 3)).to.equal(8 + 18);
+  });
+
   it('Test case', () => {
     let equation = M.equation('2+x*(y+4)+z^2');
     expect(equation(2, 4, 3)).to.equal(27);

tests/solve.js

@@ -25,6 +25,13 @@ describe('Basic math operators', () => {
   it('should work for multi-digit numbers', () => {
     expect(M.solve('12+15')).to.equal(27);
   });
+
+  it('should deal with floating precision of javascript - #5', () => {
+    expect(M.solve('0.2 + 0.1')).to.equal(0.3);
+    expect(M.solve('0.2 + 0.4')).to.equal(0.6);
+    expect(M.solve('round(floor(1.23456789/0.2)) * 0.2')).to.equal(1.2);
+    expect(M.solve('1.23456789 - (1.23456789 % 0.2)')).to.equal(1.2);
+  });
 });
 
 describe('Negative Numbers', () => {
@@ -60,11 +67,11 @@ describe('Precedence', () => {
 });
 
 describe('Functions', () => {
-  it('should work for with parantheses', () => {
+  it('should work with parantheses', () => {
     expect(M.solve('lg(4) * 5')).to.equal(10);
   });
 
-  it('should work for without parantheses', () => {
+  it('should work without parantheses', () => {
     expect(M.solve('lg4 * 5')).to.equal(10);
   });