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October 22, 2012 21:02
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JavaScript: Decimal To Fraction
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// Adapted from: http://bateru.com/news/2011/11/improved-code-for-javascript-decimal-to-fraction/ | |
function gcd(a, b) { | |
return (b) ? gcd(b, a % b) : a; | |
} | |
var decimalToFraction = function (_decimal) { | |
var top = _decimal.toString().replace(/\d+[.]/, ''); | |
var bottom = Math.pow(10, top.length); | |
if (_decimal > 1) { | |
top = +top + Math.floor(_decimal) * bottom; | |
} | |
var x = gcd(top, bottom); | |
return { | |
top : (top / x), | |
bottom : (bottom / x), | |
display : (top / x) + ':' + (bottom / x) | |
}; | |
}; |
const toLowestFraction = (fraction, denominator = 100) => {
const numerator = fraction * denominator;
let gcd = (a, b) => {
return b ? gcd(b, a % b) : a;
};
gcd = gcd(numerator, denominator);
return [ numerator / gcd, numerator / gcd ];
};
// Usage
const [numerator, numerator] = toLowestFraction(0.123);
You should include case for 1, otherwise it incorrectly returns "1/10"
var decimalToFraction = function (_decimal) {
if (_decimal == 1){
return {
top : 1,
bottom : 1,
display : 1 + ':' + 1
};
} else {
var top = _decimal.toString().replace(/\d+[.]/, '');
var bottom = Math.pow(10, top.length);
if (_decimal > 1) {
top = +top + Math.floor(_decimal) * bottom;
}
var x = gcd(top, bottom);
return {
top : (top / x),
bottom : (bottom / x),
display : (top / x) + ':' + (bottom / x)
};
}
};
This is by far the most effective solution
It is wrong every time a whole number is inputted, so it should be:
function decimalToFraction(_decimal) {
if (_decimal%1 == 0){
return {
top : _decimal,
bottom : 1,
display : _decimal + ':' + 1
};
} else {
var top = _decimal.toString().replace(/\d+[.]/, '');
var bottom = Math.pow(10, top.length);
if (_decimal > 1) {
top = +top + Math.floor(_decimal) * bottom;
}
var x = gcd(top, bottom);
return {
top : (top / x),
bottom : (bottom / x),
display : (top / x) + ':' + (bottom / x)
};
}
};
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Please use JS comments(// or /* */) because some of us who are inexperienced might want to learn how to do it, instead of copying and pasting.