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Module Js


module Js: sig .. end
Javascript binding

This module provides types and functions to interoperate with Javascript values, and gives access to Javascript standard objects.


Dealing with null and undefined values.


type +'a opt
Type of possibly null values.
type +'a optdef
Type of possibly undefined values.
val null : 'a opt
The null value.
val some : 'a -> 'a opt
Consider a value into a possibly null value.
val undefined : 'a optdef
The undefined value
val def : 'a -> 'a optdef
Consider a value into a possibly undefined value.
module type OPT = sig .. end
Signatures of a set of standard functions for manipulating optional values. 
module Opt: OPT  with type 'a t = 'a opt
Standard functions for manipulating possibly null values. 
module Optdef: OPT  with type 'a t = 'a optdef
Standard functions for manipulating possibly undefined values.

Types for specifying method and properties of Javascript objects


type +'a t
Type of Javascript objects. The type parameter is used to specify more precisely an object.
type +'a meth
Type used to specify method types: a Javascript object <m : t1 -> t2 -> ... -> tn -> t Js.meth> Js.t has a Javascript method m expecting n arguments of types t1 to tn and returns a value of type t.
type +'a gen_prop
Type used to specify the properties of Javascript objects. In practice you should rarely need this type directly, but should rather use the type abbreviations below instead.
type 'a readonly_prop = < get : 'a > gen_prop
Type of read-only properties: a Javascript object <p : t Js.readonly_prop> Js.t has a read-only property p of type t.
type 'a writeonly_prop = < set : 'a -> unit > gen_prop
Type of write-only properties: a Javascript object <p : t Js.writeonly_prop> Js.t has a write-only property p of type t.
type 'a prop = < get : 'a; set : 'a -> unit > gen_prop
Type of read/write properties: a Javascript object <p : t Js.writeonly_prop> Js.t has a read/write property p of type t.
type 'a optdef_prop = < get : 'a optdef; set : 'a -> unit > gen_prop
Type of read/write properties that may be undefined: you can set them to a value of some type t, but if you read them, you will get a value of type t optdef (that may be undefined).
type float_prop = < get : float t; set : float -> unit > gen_prop
Type of float properties: you can set them to an OCaml float, but you will get back a native Javascript number of type float t.

Object constructors


type +'a constr
A value of type (t1 -> ... -> tn -> t Js.t) Js.constr is a Javascript constructor expecting n arguments of types t1 to tn and returning a Javascript object of type t Js.t. Use the syntax extension jsnew c (e1, ..., en) to build an object using constructor c and arguments e1 to en.

Callbacks to OCaml


type (-'a, +'b) meth_callback
Type of callback functions. A function of type (u, t1 -> ... -> tn -> t) meth_callback can be called from Javascript with this bound to a value of type u and up to n arguments of types t1 to tn. The system takes care of currification, so less than n arguments can be provided. As a special case, a callback of type (t, unit -> t) meth_callback can be called from Javascript with no argument. It will behave as if it was called with a single argument of type unit.
type 'a callback = (unit, 'a) meth_callback
Type of callback functions intended to be called without a meaningful this implicit parameter.
val wrap_callback : ('a -> 'b) -> ('c, 'a -> 'b) meth_callback
Wrap an OCaml function so that it can be invoked from Javascript.
val wrap_meth_callback : ('a -> 'b -> 'c) -> ('a, 'b -> 'c) meth_callback
Wrap an OCaml function so that it can be invoked from Javascript. The first parameter of the function will be bound to the value of the this implicit parameter.

Javascript standard objects


val _true : bool t
Javascript true boolean.
val _false : bool t
Javascript false boolean.
type match_result_handle
A handle to a match result. Use function Js.match_result to get the corresponding MatchResult object. (This type is used to resolved the mutual dependency between string and array type definitions.)
type string_array
Opaque type for string arrays. You can get the actual Array object using function Js.str_array. (This type is used to resolved the mutual dependency between string and array type definitions.)
class type js_string = object .. end
Specification of Javascript string objects. 
class type regExp = object .. end
Specification of Javascript regular expression objects. 
val regExp : (js_string t -> regExp t) constr
Constructor of RegExp objects. The expression jsnew regExp (s) builds the regular expression specified by string s.
val regExp_withFlags : (js_string t -> js_string t -> regExp t) constr
Constructor of RegExp objects. The expression jsnew regExp (s, f) builds the regular expression specified by string s using flags f.
val regExp_copy : (regExp t -> regExp t) constr
Constructor of RegExp objects. The expression jsnew regExp (r) builds a copy of regular expression r.
class type ['a] js_array = object .. end
Specification of Javascript regular arrays. 
val array_empty : 'a js_array t constr
Constructor of Array objects. The expression jsnew array_empty () returns an empty array.
val array_length : (int -> 'a js_array t) constr
Constructor of Array objects. The expression jsnew array_empty (l) returns an array of length l.
val array_get : 'a #js_array t -> int -> 'a optdef
Array access: array_get a i returns the element at index i of array a. Returns undefined if there is no element at this index.
val array_set : 'a #js_array t -> int -> 'a -> unit
Array update: array_set a i v puts v at index i in array a.
class type match_result = object .. end
Specification of match result objects 
val str_array : string_array t -> js_string t js_array t
Convert an opaque string_array t object into an array of string. (Used to resolved the mutual dependency between string and array type definitions.)
val match_result : match_result_handle t -> match_result t
Convert a match result handle into a MatchResult object. (Used to resolved the mutual dependency between string and array type definitions.)
class type number = object .. end
Specification of Javascript number objects. 
val number_of_float : float -> number t
Conversion of OCaml floats to Javascript number objects.
val float_of_number : number t -> float
Conversion of Javascript number objects to OCaml floats.
class type date = object .. end
Specification of Javascript date objects. 
val date_now : date t constr
Constructor of Date objects: new date_now () returns a Date object initialized with the current date.
val date_fromTimeValue : (float -> date t) constr
Constructor of Date objects: new date_fromTimeValue (t) returns a Date object initialized with the time value t.
val date_month : (int -> int -> date t) constr
Constructor of Date objects: new date_fromTimeValue (y, m) returns a Date object corresponding to year y and month m.
val date_day : (int -> int -> int -> date t) constr
Constructor of Date objects: new date_fromTimeValue (y, m, d) returns a Date object corresponding to year y, month m and day d.
val date_hour : (int -> int -> int -> int -> date t) constr
Constructor of Date objects: new date_fromTimeValue (y, m, d, h) returns a Date object corresponding to year y to hour h.
val date_min : (int -> int -> int -> int -> int -> date t) constr
Constructor of Date objects: new date_fromTimeValue (y, m, d, h, m') returns a Date object corresponding to year y to minute m'.
val date_sec : (int -> int -> int -> int -> int -> int -> date t) constr
Constructor of Date objects: new date_fromTimeValue (y, m, d, h, m', s) returns a Date object corresponding to year y to second s.
val date_ms : (int -> int -> int -> int -> int -> int -> int -> date t) constr
Constructor of Date objects: new date_fromTimeValue (y, m, d, h, m', s, ms) returns a Date object corresponding to year y to millisecond ms.
class type date_constr = object .. end
Specification of the date constructor, considered as an object. 
val date : date_constr t
The date constructor, as an object.
class type math = object .. end
Specification of Javascript math object. 
val math : math t
The Math object

Standard Javascript functions


val decodeURI : js_string t -> js_string t
Decode a URI: replace by the corresponding byte all escape sequences but the ones corresponding to a URI reserved character and convert the string from UTF-8 to UTF-16.
val decodeURIComponent : js_string t -> js_string t
Decode a URIComponent: replace all escape sequences by the corresponding byte and convert the string from UTF-8 to UTF-16.
val encodeURI : js_string t -> js_string t
Encode a URI: convert the string to UTF-8 and replace all unsafe bytes by the corresponding escape sequence.
val encodeURIComponent : js_string t -> js_string t
Same as encodeURI, but also encode URI reserved characters.
val escape : js_string t -> js_string t
Escape a string: unsafe UTF-16 code points are replaced by 2-digit and 4-digit escape sequences.
val unescape : js_string t -> js_string t
Unescape a string: 2-digit and 4-digit escape sequences are replaced by the corresponding UTF-16 code point.

Conversion functions between Javascript and OCaml types


val bool : bool -> bool t
Conversion of booleans from OCaml to Javascript.
val to_bool : bool t -> bool
Conversion of booleans from Javascript to OCaml.
val string : string -> js_string t
Conversion of strings from OCaml to Javascript. (The OCaml string is considered to be encoded in UTF-8 and is converted to UTF-16.)
val to_string : js_string t -> string
Conversion of strings from Javascript to OCaml.
val float : float -> float t
Conversion of OCaml floats to Javascript numbers.
val to_float : float t -> float
Conversion of Javascript numbers to OCaml floats.
val array : 'a array -> 'a js_array t
Conversion of arrays from OCaml to Javascript.
val to_array : 'a js_array t -> 'a array
Conversion of arrays from Javascript to OCaml.
val bytestring : string -> js_string t
Conversion of strings of bytes from OCaml to Javascript. (Each byte will be converted in an UTF-16 code point.)
val to_bytestring : js_string t -> string
Conversion of strings of bytes from Javascript to OCaml. (The Javascript string should only contain UTF-16 code points below 255.)

Convenience coercion functions


val coerce : 'a -> ('a -> 'b Opt.t) -> ('a -> 'b) -> 'b
Apply a possibly failing coercion function. coerce v c f attempts to apply coercion c to value v. If the coercion returns null, function f is called.
val coerce_opt : 'a Opt.t -> ('a -> 'b Opt.t) -> ('a -> 'b) -> 'b
Apply a possibly failing coercion function. coerce_opt v c f attempts to apply coercion c to value v. If v is null or the coercion returns null, function f is called. Typical usage is the following: 
Js.coerce_opt (Dom_html.getElementById id)
      Dom_html.CoerceTo.div (fun _ -> assert false)


Type checking operators.


val typeof : < .. > t -> js_string t
Returns the type of a Javascript object.
val instanceof : < .. > t -> 'a constr -> bool
Tests whether a Javascript object is an instance of a given class.

Unsafe operations.


module Unsafe: sig .. end
Unsafe Javascript operations