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Feature/modulo support #6

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Feature/modulo support #6

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fa31649
Add modulo operation support to library
achtaitaipai May 25, 2023
a4c7c8e
Update scenarios.js to include modulo tests
achtaitaipai May 25, 2023
ef25c23
update documentation to include modulo
achtaitaipai May 25, 2023
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3 changes: 2 additions & 1 deletion readme.md
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,7 @@ var result = stringMath("2+2");
* `/` division sign
* `+` plus sign
* `-` subtraction sign
* `%` modulo sign
* `(` and `)` parentheses

##### `callback` **[Function]** *(optional)* *(synchronous)*
Expand All @@ -92,7 +93,7 @@ If the math formula is of correct type and is valid, it returns the [Number] res
# Tips
* the arithmetic **order of operations** is respected:
* *parentheses first*
* *then division and multiplication (from left to right)*
* *then division, multiplication and modulo (from left to right)*
* *then addition and subtraction (from left to right)*
* the multiplication sign can be omitted before parentheses; `4(2+1)`; *equals to `4*(2+1)`*
* the following signs combinations are allowed:
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16 changes: 8 additions & 8 deletions string-math.js
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@@ -1,6 +1,6 @@
function stringMath(eq, callback) {
if (typeof eq !== 'string') return handleCallback(new TypeError('The [String] argument is expected.'), null);
const mulDiv = /([+-]?\d*\.?\d+(?:e[+-]\d+)?)\s*([*/])\s*([+-]?\d*\.?\d+(?:e[+-]\d+)?)/;
const mulDivMod = /([+-]?\d*\.?\d+(?:e[+-]\d+)?)\s*([*/%])\s*([+-]?\d*\.?\d+(?:e[+-]\d+)?)/;
const plusMin = /([+-]?\d*\.?\d+(?:e[+-]\d+)?)\s*([+-])\s*([+-]?\d*\.?\d+(?:e[+-]\d+)?)/;
const parentheses = /(\d)?\s*\(([^()]*)\)\s*/;
var current;
Expand All @@ -14,21 +14,21 @@ function stringMath(eq, callback) {
function fParentheses(eq) {
while (eq.search(parentheses) !== -1) {
eq = eq.replace(parentheses, function (a, b, c) {
c = fMulDiv(c);
c = fMulDivMod(c);
c = fPlusMin(c);
return typeof b === 'string' ? b + '*' + c : c;
});
}
eq = fMulDiv(eq);
eq = fMulDivMod(eq);
eq = fPlusMin(eq);
return eq;
}

function fMulDiv(eq) {
while (eq.search(mulDiv) !== -1) {
eq = eq.replace(mulDiv, function (a) {
const sides = mulDiv.exec(a);
const result = sides[2] === '*' ? sides[1] * sides[3] : sides[1] / sides[3];
function fMulDivMod(eq) {
while (eq.search(mulDivMod) !== -1) {
eq = eq.replace(mulDivMod, function (a) {
const sides = mulDivMod.exec(a);
const result = sides[2] === '*' ? sides[1] * sides[3] : sides[2] === '/' ? sides[1] / sides[3] : sides[1] % sides [3];
return result >= 0 ? '+' + result : result;
});
}
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26 changes: 24 additions & 2 deletions tests/scenarios.js
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Expand Up @@ -148,5 +148,27 @@ module.exports = [
{expression:".5e+123 * .25e-123",result:0.125},
{expression:"(2e+2)",result:200},
{expression:"123/1000/2000/3000",result:2.05e-8},
{expression:"(2.5e-2*(.25e+2*(.05e+5*5e-2)))",result:156.25}
];
{expression:"(2.5e-2*(.25e+2*(.05e+5*5e-2)))",result:156.25},
{expression:"10 % 3",result:1},
{expression:"7 % 2",result:1},
{expression:"15 % 4",result:3},
{expression:"-10 % 3",result:-1},
{expression:"-7 % 2",result:-1},
{expression:"-15 % 4",result:-3},
{expression:"10 % -3",result:1},
{expression:"7 % -2",result:1},
{expression:"15 % -4",result:3},
{expression:"-10 % -3",result:-1},
{expression:"-7 % -2",result:-1},
{expression:"-15 % -4",result:-3},
{expression:"(10 + 4) % 6",result:2},
{expression:"15 % (3 + 2)",result:0},
{expression:"(8 - 3) % (2 + 2)",result:1},
{expression:"((7 % 3) + (4 % 2)) % 2",result:1},
{expression:"10 % 3 + 5 % 2",result:2},
{expression:"((8 % 3) + 4) % (2 % 2 + 1)",result:0},
{expression:"((3 % 2) * 5) % 4",result:1},
{expression:"(6 + 7 * 2) % (3 + 1 * 2)",result:0},
{expression:"(9 % 4) * (6 % 2) - (8 % 3)",result:-2},
{expression:"(((15 % 6) + 8) * 2) % 7",result:1}
];