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Numbers' methods and new literals in es6
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// Octals 0 + o + integer | |
0o8 | |
// Binary 0 + b + integer | |
0b11 | |
// ParseInt doesn't support binary literals | |
parseInt('0b11', 2); // 0 | |
// Instead use Number() | |
Number('0b11'); // 3 | |
// Or remove prefix | |
parseInt('11', 2); // 3 | |
// Test if number is instance of Number, not (-)Infinity nor NaN | |
Number.isFinite(Infinity); // False | |
Number.isFinite(123); // True | |
// Doesn't coerce its parameter whereas the global does | |
isFinite('123'); // true | |
Number.isFinite('123'); // false | |
// Test if the object is NaN | |
Number.isNaN(NaN); // true | |
// Doesn't coerce its parameter to number | |
Number.isNaN('123'); // false | |
isNaN('123'); // true | |
// Same parseFloat and parseInt but now within Number | |
Number.parseFloat('22.5'); // 22.5 | |
Number.parseInt('22.5'); // 22 | |
// NUMBER.EPSILON specifies a margin of error when comparing floats | |
Math.abs(3.000000000000004 - 3) < Number.EPSILON; // true, so probably they are equal | |
Math.abs(4 - 3) < Number.EPSILON; // false | |
// Know if it's an integer (without decimal part) | |
Number.isInteger(33); // true | |
Number.isInteger('33'); // false | |
// Safe integers between range (−2^53, 2^53) | |
Number.isSafeInteger(Math.pow(2, 53) - 1); // true | |
Number.isSafeInteger(Math.pow(2, 53)); // false | |
Number.MAX_SAFE_INTEGER = Math.pow(2, 53) - 1; | |
Number.MIN_SAFE_INTEGER = -Number.MAX_SAFE_INTEGER; | |
// A calculation (a + b = c) gives a safe result if | |
Number.isSafeInteger(a) && | |
Number.isSafeInteger(b) && | |
Number.isSafeInteger(a + b); |
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