Module Js.Float

module Float: Js_float
Provide utilities for manipulating JS types

val _NaN : float
The special value "Not a Number"
  • See also MDN
  • val isNaN : float -> bool
    Tests if the given value is _NaN Note that both _NaN = _NaN and _NaN == _NaN will return false. isNaN is therefore necessary to test for _NaN. Returns true if the given value is _NaN, false otherwise
  • See also MDN
  • val isFinite : float -> bool
    Tests if the given value is finite Returns true if the given value is a finite number, false otherwise
  • See also MDN
  •  
    (* returns [false] *)
    let _ = Js.Float.isFinite infinity
    
    (* returns [false] *)
    let _ = Js.Float.isFinite neg_infinity
    
    (* returns [false] *)
    let _ = Js.Float.isFinite _NaN
    
    (* returns [true] *)
    let _ = Js.Float.isFinite 1234
    
    val toExponential : float -> string
    Formats a float using exponential (scientific) notation Returns a string representing the given value in exponential notation
  • Raises RangeError if digits is not in the range [0, 20] (inclusive)
  • See also MDN
  •  
    (* prints "7.71234e+1" *)
    let _ = Js.log @@ Js.Float.toExponential 77.1234
    
    (* prints "7.7e+1" *)
    let _ = Js.log @@ Js.Float.toExponential 77.
    
    val toExponentialWithPrecision : float -> digits:int -> string
    Formats a float using exponential (scientific) notation digits specifies how many digits should appear after the decimal point. The value must be in the range [0, 20] (inclusive). Returns a string representing the given value in exponential notation The output will be rounded or padded with zeroes if necessary.
  • Raises RangeError if digits is not in the range [0, 20] (inclusive)
  • See also MDN
  •  
    (* prints "7.71e+1" *)
    let _ = Js.log @@ Js.Float.toExponentialWithPrecision 77.1234 ~digits:2
    
    val toFixed : float -> string
    Formats a float using fixed point notation Returns a string representing the given value in fixed-point notation (usually)
  • Raises RangeError if digits is not in the range [0, 20] (inclusive)
  • See also MDN
  •  
    (* prints "12346" (note the rounding) *)
    let _ = Js.log @@ Js.Float.toFixed 12345.6789
    
    (* print "1.2e+21" *)
    let _ = Js.log @@ Js.Float.toFixed 1.2e21
    
    val toFixedWithPrecision : float -> digits:int -> string
    Formats a float using fixed point notation digits specifies how many digits should appear after the decimal point. The value must be in the range [0, 20] (inclusive). Defaults to 0. Returns a string representing the given value in fixed-point notation (usually) The output will be rounded or padded with zeroes if necessary.
  • Raises RangeError if digits is not in the range [0, 20] (inclusive)
  • See also MDN
  •  
    (* prints "12345.7" (note the rounding) *)
    let _ = Js.log @@ Js.Float.toFixedWithPrecision 12345.6789 ~digits:1
    
    (* prints "0.00" (note the added zeroes) *)
    let _ = Js.log @@ Js.Float.toFixedWithPrecision 0. ~digits:2
    
    val toPrecision : float -> string
    Formats a float using some fairly arbitrary rules Returns a string representing the given value in fixed-point (usually) toPrecision differs from toFixed in that the former will format the number with full precision, while the latter will not output any digits after the decimal point.
  • Raises RangeError if digits is not in the range accepted by this function (what do you mean "vague"?)
  • See also MDN
  •  
    (* prints "12345.6789" *)
    let _ = Js.log @@ Js.Float.toPrecision 12345.6789
    
    (* print "1.2e+21" *)
    let _ = Js.log @@ Js.Float.toPrecision 1.2e21
    
    val toPrecisionWithPrecision : float -> digits:int -> string
    Formats a float using some fairly arbitrary rules digits specifies how many digits should appear in total. The value must between 0 and some arbitrary number that's hopefully at least larger than 20 (for Node it's 21. Why? Who knows). Returns a string representing the given value in fixed-point or scientific notation The output will be rounded or padded with zeroes if necessary. toPrecisionWithPrecision differs from toFixedWithPrecision in that the former will count all digits against the precision, while the latter will count only the digits after the decimal point. toPrecisionWithPrecision will also use scientific notation if the specified precision is less than the number for digits before the decimal point.
  • Raises RangeError if digits is not in the range accepted by this function (what do you mean "vague"?)
  • See also MDN
  •  
    (* prints "1e+4" *)
    let _ = Js.log @@ Js.Float.toPrecisionWithPrecision 12345.6789 ~digits:1
    
    (* prints "0.0" *)
    let _ = Js.log @@ Js.Float.toPrecisionWithPrecision 0. ~digits:2
    
    val toString : float -> string
    Formats a float as a string Returns a string representing the given value in fixed-point (usually)
  • See also MDN
  •  
    (* prints "12345.6789" *)
    let _ = Js.log @@ Js.Float.toString 12345.6789
    
    val toStringWithRadix : float -> radix:int -> string
    Formats a float as a string radix specifies the radix base to use for the formatted number. The value must be in the range [2, 36] (inclusive). Returns a string representing the given value in fixed-point (usually)
  • Raises RangeError if radix is not in the range [2, 36] (inclusive)
  • See also MDN
  •  
    (* prints "110" *)
    let _ = Js.log @@ Js.Float.toStringWithRadix 6. ~radix:2
    
    (* prints "11.001000111101011100001010001111010111000010100011111" *)
    let _ = Js.log @@ Js.Float.toStringWithRadix 3.14 ~radix:2
    
    (* prints "deadbeef" *)
    let _ = Js.log @@ Js.Float.toStringWithRadix 3735928559. ~radix:16
    
    (* prints "3f.gez4w97ry0a18ymf6qadcxr" *)
    let _ = Js.log @@ Js.Float.toStringWithRadix 123.456 ~radix:36
    
    val fromString : string -> float
    Parses the given string into a float using JavaScript semantics Returns the number as a float if successfully parsed, _NaN otherwise.
     
    (* returns 123 *)
    let _ = Js.Float.fromString "123"
    
    (* returns 12.3 *)
    let _ = Js.Float.fromString "12.3"
    
    (* returns 0 *)
    let _ = Js.Float.fromString ""
    
    (* returns 17 *)
    let _ = Js.Float.fromString "0x11"
    
    (* returns 3 *)
    let _ = Js.Float.fromString "0b11"
    
    (* returns 9 *)
    let _ = Js.Float.fromString "0o11"
    
    (* returns [_NaN] *)
    let _ = Js.Float.fromString "foo"
    
    (* returns [_NaN] *)
    let _ = Js.Float.fromString "100a"