The nearest 32-bit single precision float representation of the given number.
high precision. However, sometimes you may be working with 32-bit floating-point
numbers, for example if you are reading values from a
can create confusion: Checking a 64-bit float and a 32-bit float for equality may fail
even though the numbers are seemingly identical.
To solve this,
Math.fround() can be used to cast the 64-bit float to a
just performs a "round to even" on the 23rd bit of the mantissa, and sets all following
mantissa bits to
0. If the number is outside the range of a 32-bit float,
-Infinity is returned.
fround() is a static method of
Math, you always use
Math.fround(), rather than as a method of a
you created (
Math is not a constructor).
The number 1.5 can be precisely represented in the binary numeral system, and is identical in 32-bit and 64-bit:
Math.fround(1.5); // 1.5 Math.fround(1.5) === 1.5; // true
However, the number 1.337 cannot be precisely represented in the binary numeral system, so it differs in 32-bit and 64-bit:
Math.fround(1.337); // 1.3370000123977661 Math.fround(1.337) === 1.337; // false
is too big for a 32-bit float, so
Infinity is returned:
2 ** 150; // 1.42724769270596e+45 Math.fround(2 ** 150); // Infinity
If the parameter cannot be converted to a number, or it is not-a-number (
Math.fround() will return
Math.fround('abc'); // NaN Math.fround(NaN); // NaN
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