Get around floating point precision of JavaScript fixes #5
Fix `equation` not working on parentheses wrapped variables Fixed `parseExpression` not working correctly on nested function operators
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parent
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36
dist/index.js
vendored
36
dist/index.js
vendored
@ -72,7 +72,11 @@ var Equation = {
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var stack = parseExpression(expression);
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var stack = parseExpression(expression);
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var variables = [];
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var variables = [];
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stack.forEach(function (a) {
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stack.forEach(function varCheck(a) {
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if (Array.isArray(a)) {
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return a.forEach(varCheck);
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}
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if (typeof a === 'string' && !_.isNumber(a) && !_operators2['default'][a] && a === a.toLowerCase()) {
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if (typeof a === 'string' && !_.isNumber(a) && !_operators2['default'][a] && a === a.toLowerCase()) {
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// grouped variables like (y) need to have their parantheses removed
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// grouped variables like (y) need to have their parantheses removed
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variables.push(_.removeSymbols(a));
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variables.push(_.removeSymbols(a));
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@ -161,22 +165,30 @@ var parseExpression = function parseExpression(expression) {
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}
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}
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// it's probably a function with a length more than one
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// it's probably a function with a length more than one
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if (!_.isNumber(cur) && !_operators2['default'][cur] && cur !== '.') {
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if (!_.isNumber(cur) && !_operators2['default'][cur] && cur !== '.' && cur !== '(' && cur !== ')') {
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record += cur;
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record += cur;
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} else if (record.length) {
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} else if (record.length) {
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stack.push(record, cur);
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stack.push(record, cur);
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record = '';
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record = '';
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} else if (_.isNumber(stack[stack.length - 1]) && (_.isNumber(cur) || cur === '.')) {
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} else if (_.isNumber(stack[past]) && (_.isNumber(cur) || cur === '.')) {
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stack[stack.length - 1] += cur;
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stack[past] += cur;
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// negation sign
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} else if (stack[past] === '-') {
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} else if (stack[past] === '-') {
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var beforeSign = stack[stack.length - 2];
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var beforeSign = stack[past - 1];
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// 2 / -5 is OK, pass
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if (_operators2['default'][beforeSign]) {
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if (_operators2['default'][beforeSign]) {
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stack[past] += cur;
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stack[past] += cur;
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// (2+1) - 5 becomes (2+1) + -5
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} else if (beforeSign === ')') {
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} else if (beforeSign === ')') {
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stack[past] = '+';
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stack[past] = '+';
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stack.push('-' + cur);
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stack.push('-' + cur);
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// 2 - 5 is also OK, pass
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} else if (_.isNumber(beforeSign)) {
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} else if (_.isNumber(beforeSign)) {
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stack.push(cur);
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stack.push(cur);
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} else {
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} else {
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@ -353,7 +365,7 @@ var evaluate = function evaluate(stack) {
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var leftArguments = stack.slice(0, left),
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var leftArguments = stack.slice(0, left),
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rightArguments = stack.slice(left + 1);
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rightArguments = stack.slice(left + 1);
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return (_operators$op = _operators2['default'][op]).fn.apply(_operators$op, _toConsumableArray(leftArguments).concat(_toConsumableArray(rightArguments)));
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return fixFloat((_operators$op = _operators2['default'][op]).fn.apply(_operators$op, _toConsumableArray(leftArguments).concat(_toConsumableArray(rightArguments))));
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};
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};
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/**
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/**
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@ -413,5 +425,17 @@ var replaceConstants = function replaceConstants(expression) {
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});
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});
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};
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};
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/**
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* Fixes JavaScript's floating point precisions - Issue #5
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*
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* @param {Number} number
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* The number to fix
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* @return {Number}
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* Fixed number
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*/
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var fixFloat = function fixFloat(number) {
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return +number.toFixed(15);
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};
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exports['default'] = Equation;
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exports['default'] = Equation;
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module.exports = exports['default'];
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module.exports = exports['default'];
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10
dist/operators.js
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10
dist/operators.js
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@ -109,6 +109,16 @@ exports['default'] = {
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fn: Math.cot,
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fn: Math.cot,
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format: '10',
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format: '10',
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precedence: -1
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precedence: -1
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},
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round: {
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fn: Math.round,
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format: '10',
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precedence: -1
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},
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floor: {
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fn: Math.floor,
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format: '10',
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precedence: -1
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}
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}
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};
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};
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module.exports = exports['default'];
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module.exports = exports['default'];
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11
dist/tests/solve.js
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11
dist/tests/solve.js
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@ -32,6 +32,13 @@ describe('Basic math operators', function () {
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it('should work for multi-digit numbers', function () {
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it('should work for multi-digit numbers', function () {
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_expect.expect(_M2['default'].solve('12+15')).to.equal(27);
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_expect.expect(_M2['default'].solve('12+15')).to.equal(27);
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});
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});
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it('should deal with floating precision of javascript - #5', function () {
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_expect.expect(_M2['default'].solve('0.2 + 0.1')).to.equal(0.3);
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_expect.expect(_M2['default'].solve('0.2 + 0.4')).to.equal(0.6);
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_expect.expect(_M2['default'].solve('round(floor(1.23456789/0.2)) * 0.2')).to.equal(1.2);
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_expect.expect(_M2['default'].solve('1.23456789 - (1.23456789 % 0.2)')).to.equal(1.2);
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});
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});
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});
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describe('Negative Numbers', function () {
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describe('Negative Numbers', function () {
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@ -67,11 +74,11 @@ describe('Precedence', function () {
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});
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});
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describe('Functions', function () {
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describe('Functions', function () {
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it('should work for with parantheses', function () {
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it('should work with parantheses', function () {
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_expect.expect(_M2['default'].solve('lg(4) * 5')).to.equal(10);
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_expect.expect(_M2['default'].solve('lg(4) * 5')).to.equal(10);
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});
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});
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it('should work for without parantheses', function () {
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it('should work without parantheses', function () {
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_expect.expect(_M2['default'].solve('lg4 * 5')).to.equal(10);
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_expect.expect(_M2['default'].solve('lg4 * 5')).to.equal(10);
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});
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});
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40
lib/index.js
40
lib/index.js
@ -49,7 +49,11 @@ let Equation = {
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let stack = parseExpression(expression);
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let stack = parseExpression(expression);
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let variables = [];
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let variables = [];
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stack.forEach(a => {
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stack.forEach(function varCheck(a) {
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if (Array.isArray(a)) {
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return a.forEach(varCheck);
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}
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if (typeof a === 'string' && !_.isNumber(a) &&
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if (typeof a === 'string' && !_.isNumber(a) &&
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!operators[a] && a === a.toLowerCase()) {
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!operators[a] && a === a.toLowerCase()) {
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// grouped variables like (y) need to have their parantheses removed
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// grouped variables like (y) need to have their parantheses removed
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@ -125,23 +129,32 @@ const parseExpression = expression => {
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}
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}
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// it's probably a function with a length more than one
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// it's probably a function with a length more than one
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if (!_.isNumber(cur) && !operators[cur] && cur !== '.') {
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if (!_.isNumber(cur) && !operators[cur] && cur !== '.' &&
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cur !== '(' && cur !== ')') {
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record += cur;
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record += cur;
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} else if (record.length) {
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} else if (record.length) {
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stack.push(record, cur);
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stack.push(record, cur);
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record = '';
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record = '';
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} else if (_.isNumber(stack[stack.length - 1]) &&
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} else if (_.isNumber(stack[past]) &&
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(_.isNumber(cur) || cur === '.')) {
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(_.isNumber(cur) || cur === '.')) {
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stack[stack.length - 1] += cur;
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stack[past] += cur;
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} else if (stack[past] === '-') {
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const beforeSign = stack[stack.length - 2];
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// negation sign
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} else if (stack[past] === '-') {
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const beforeSign = stack[past - 1];
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// 2 / -5 is OK, pass
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if (operators[beforeSign]) {
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if (operators[beforeSign]) {
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stack[past] += cur;
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stack[past] += cur;
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// (2+1) - 5 becomes (2+1) + -5
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} else if (beforeSign === ')') {
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} else if (beforeSign === ')') {
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stack[past] = '+';
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stack[past] = '+';
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stack.push(`-${cur}`);
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stack.push(`-${cur}`);
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// 2 - 5 is also OK, pass
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} else if (_.isNumber(beforeSign)) {
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} else if (_.isNumber(beforeSign)) {
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stack.push(cur);
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stack.push(cur);
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} else {
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} else {
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@ -272,12 +285,13 @@ const evaluate = stack => {
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if (!op) {
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if (!op) {
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return stack[0];
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return stack[0];
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}
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}
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const { left } = formatInfo(op);
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const { left } = formatInfo(op);
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let leftArguments = stack.slice(0, left),
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let leftArguments = stack.slice(0, left),
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rightArguments = stack.slice(left + 1);
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rightArguments = stack.slice(left + 1);
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return operators[op].fn(...leftArguments, ...rightArguments);
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return fixFloat(operators[op].fn(...leftArguments, ...rightArguments));
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};
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};
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/**
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/**
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@ -315,4 +329,16 @@ const replaceConstants = expression => {
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});
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});
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};
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};
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/**
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* Fixes JavaScript's floating point precisions - Issue #5
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*
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* @param {Number} number
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* The number to fix
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* @return {Number}
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* Fixed number
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*/
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const fixFloat = number => {
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return +number.toFixed(15);
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};
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export default Equation;
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export default Equation;
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@ -88,5 +88,15 @@ export default {
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fn: Math.cot,
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fn: Math.cot,
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format: '10',
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format: '10',
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precedence: -1
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precedence: -1
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},
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'round': {
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fn: Math.round,
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format: '10',
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precedence: -1
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},
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'floor': {
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fn: Math.floor,
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format: '10',
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precedence: -1
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}
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}
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};
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};
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@ -25,6 +25,13 @@ describe('Basic math operators', () => {
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it('should work for multi-digit numbers', () => {
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it('should work for multi-digit numbers', () => {
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expect(M.solve('12+15')).to.equal(27);
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expect(M.solve('12+15')).to.equal(27);
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});
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});
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it('should deal with floating precision of javascript - #5', () => {
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expect(M.solve('0.2 + 0.1')).to.equal(0.3);
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expect(M.solve('0.2 + 0.4')).to.equal(0.6);
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expect(M.solve('round(floor(1.23456789/0.2)) * 0.2')).to.equal(1.2);
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expect(M.solve('1.23456789 - (1.23456789 % 0.2)')).to.equal(1.2);
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});
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});
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});
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describe('Negative Numbers', () => {
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describe('Negative Numbers', () => {
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@ -60,11 +67,11 @@ describe('Precedence', () => {
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});
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});
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describe('Functions', () => {
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describe('Functions', () => {
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it('should work for with parantheses', () => {
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it('should work with parantheses', () => {
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expect(M.solve('lg(4) * 5')).to.equal(10);
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expect(M.solve('lg(4) * 5')).to.equal(10);
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});
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});
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it('should work for without parantheses', () => {
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it('should work without parantheses', () => {
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expect(M.solve('lg4 * 5')).to.equal(10);
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expect(M.solve('lg4 * 5')).to.equal(10);
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});
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});
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