I am presently translating some code from C++ to Javascript and it involves quite a few floating point calculations. The program uses several built-in machine constants to help it quantify and limit computer round-off error. For example, it includes the constants DBL_MIN and DBL_EPSILON from the <cfloat> library within C++.

I am now wondering: does Javascript offer these constants as built-in values too? I suppose I could calculate them myself, by brute force, but if these values are already available, it would help me keep the Javascript version shorter.

Does Javascript provide built-in, comparable values for DBL_MIN and DBL_EPSILON? (If so, how do I access them?)



11 Years
Discussion Span
Last Post by MidiMagic

You can always peek into the header files of the compiler you are using to find out the value of those in-built constants and put the same in a JS file and include that file.

Something like:

// Vars.js
var DB_EPSILON = 0.00000000123
var DB_MIN = 0.125
  <script src="Vars.js"></script>
<!-- code -->

If you want to know the actual minimum value of the smallest value the current running JavaScript can actually use, it will tell you.

Use: Number.MIN_VALUE JS provides the following constants: Number.MIN_VALUE :
The smallest positive value which can be stored. It is close to 5E-324 Number.MAX_VALUE :
The largest positive value which can be stored. It is close to 1.79E+308 Number.NEGATIVE_INFINITY :
Returns the internal representation for negative infinity Number.POSITIVE_INFINITY :
Returns the internal representation for positive infinity Math.E :
Returns the natural base. Math.LN10 :
Returns the natural log of 10. Math.LN2 :
Returns the natural log of 2. Math.LOG10E :
Returns the common log of the natural base. Math.LOG2E :
Returns the binary-base log of the natural base. Math.PI :
Returns the value of pi. Math.SQRT1_2 :
Returns the square root of one half. Math.SQRT2 :
Returns the sqiare root of 2.

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