EN
JavaScript - universal way to compare values (boolean, number, string, Date, etc.)
6 points
In this article, we're going to have a look at how to compare two values when we want to sort them in JavaScript.
Presented comparison result we should understand the following way:
-1when first value is smaller than second one,0when values are equal,+1when first value is greater than second one.
Quick solution:
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const compareValues = (a, b) => {2
if (a < b) return -1;3
if (a > b) return +1;4
return 0;5
};6
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// Usage example:9
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console.log(compareValues(2, 1)); // +1Note: the presented function compares in correct way ISO 8601 string dates also.
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const compareValues = (a, b) => {2
if (a < b) return -1;3
if (a > b) return +1;4
return 0;5
};6
7
8
// Usage example:9
10
// Booleans:11
console.log(compareValues(true, true)); // 0 // true is equal to true12
console.log(compareValues(true, false)); // +1 // false is before true (because 0 means false, other values mean true)13
console.log(compareValues(false, true)); // -1 // true is after false (because 0 means false, other values mean true)14
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// Numbers:16
console.log(compareValues(1, 1)); // 0 // 1 is equal to 117
console.log(compareValues(2, 1)); // +1 // 2 is after 118
console.log(compareValues(1, 2)); // -1 // 1 is before 219
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// Strings:21
console.log(compareValues('aaa', 'aaa')); // 0 // 'aaa' is equal to 'aaa'22
console.log(compareValues('aab', 'aaa')); // +1 // 'aab' is after 'aaa'23
console.log(compareValues('aaa', 'aab')); // -1 // 'aaa' is before 'aab'24
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// Dates:26
console.log(compareValues(new Date(2023, 1, 1), new Date(2023, 1, 1))); // 0 // 2023-01-01 is equal to 2023-01-0127
console.log(compareValues(new Date(2023, 1, 2), new Date(2023, 1, 1))); // +1 // 2023-01-02 is after 2023-01-0128
console.log(compareValues(new Date(2023, 1, 1), new Date(2023, 1, 2))); // -1 // 2023-01-01 is before 2023-01-02
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const compareValues = (a, b) => {2
if (a < b) return -1;3
if (a > b) return +1;4
return 0;5
};6
7
8
// Usage example:9
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const booleans = [true, false, true];11
const numbers = [1, 3, 2];12
const strings = ['aaa', 'aac', 'aab'];13
const dates = [new Date(2023, 1, 1), new Date(2023, 1, 3), new Date(2023, 1, 2)];14
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booleans.sort(compareValues);16
numbers.sort(compareValues);17
strings.sort(compareValues);18
dates.sort(compareValues);19
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console.log(booleans); // false, true, true21
console.log(numbers); // 1, 2, 322
console.log(strings); // aaa, aab, aac23
console.log(dates.map(date => date.toISOString().substring(0, 10))); // 2023-01-31, 2023-02-01, 2023-02-02
