rebuild

equation.js

@@ -247,10 +247,14 @@ var Equation = {
     */
   equation: function equation(expression) {
     var stack = parseExpression(expression);
+    console.log(stack);
     var variables = [];
 
-    stack.forEach(function (a) {
-      if (typeof a === 'string' && !_.isNumber(a) && !_operators2['default'][a] && a === a.toLowerCase()) {
+    stack.forEach(function varCheck(a) {
+      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));
       }
@@ -261,15 +265,30 @@ 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;
     };
   },
 
@@ -327,33 +346,50 @@ 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 {
@@ -364,6 +400,10 @@ 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);
   }
 
@@ -530,7 +570,7 @@ 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))));
 };
 
 /**
@@ -590,8 +630,31 @@ 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'];
 },{"./constants":1,"./helpers":2,"./operators":4,"./readstream":5}],4:[function(require,module,exports){
 'use strict';
 
@@ -704,6 +767,16 @@ 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'];