js.component

Lodash - language

About

These functions extend the 4D language-related commands by making it more convenient when working with values and types.

API

.bind()

.bind(func : Callable { ; thisObj : any { ; …partialParams : any }}) : cs.js.Binder

Returns an object whose .call(), .apply() and .f() functions will call func.apply(). If thisObj is null, the first parameter passed to .call() or .apply() will be used as the This object, otherwise thisObj will be used as the This object.

If partialParams are passed, they are prepended to whatever parameters are passed to the bound function.

Examples

// Bind `This` to $person
$person:=New object("first"; "Laurent"; "last"; "Ribardière")
$greeter:=_.bind(Formula($1+" "+This.first+" "+This.last+$2); $person; "Hello")
$greeting:=$greeter.call(Null; "!")
// => "Hello Laurent Ribardière!"

// `This` must be passed in
$person:=New object("first"; "Laurent"; "last"; "Ribardière")
$greeter:=_.bind(Formula($1+" "+This.first+" "+This.last+$2); Null; "Hello")
$greeting:=$greeter.call($person; "!")
// => "Hello Laurent Ribardière!"

// No `This`
$greeter:=_.bind(Formula($1+" "+$2+$3); Null; "Hello")
$greeting:=$func.call(Null; "Laurent"; "!")
// => "Hello Laurent!"

.bindRight()

.bindRight(func : Callable { ; thisObj : any { ; …partialParams : any }}) : cs.js.Binder

This is the same as .bind(), but if partialParams are passed, they are appended rather than prepended to whatever parameters are passed to the bound function.

Examples

$person:=New object("first"; "Laurent"; "last"; "Ribardière")
$greeter:=_.bindRight(Formula($1+" "+This.first+" "+This.last+$2); $person; "!")
$greeting:=$greeter.call(Null; "Hello") // => "Hello Laurent Ribardière!"

.bool()

.bool(value : any { ; expect : Boolean }) : Boolean

Sometimes you want to know specifically if a value is the boolean value true or false. This function allows you to test for that in one line.

If expect is not passed, it defaults to true. If value is a boolean, it is tested against expect and the result is returned. Otherwise false is returned.

NOTE

Do not confuse _.bool() with 4D’s Bool() command!

.equal()

.equal(value : any; compare : any { ; strict : Boolean }) : Boolean

Compares value with compare and returns whether they have the same value.

The beauty of this function is you can throw anything at it, even types that are not compatible, and it will not generate an error. In addition, you can use this one function to compare values of any type, including ones that cannot be compared with =.

Comparisons are performed as follows:

  • If value and compare are not type-compatible, false is returned.

  • Strings: If strict is true, case/diacritical comparison is done, otherwise a non-case/diacritical = comparison is done.

  • Objects: They must be of the same class, have the same keys, and all of the values must recursively pass _.equal(). If strict is true, string comparisons are case/diacritical-sensitive.

  • Collections: Collection.equalopen in new window is used. If strict is true, ck diacritical is passed.

  • Blobs: Size and SHA256 digestopen in new window must match.

  • Pictures: Equal picturesopen in new window is used.

  • Other types: They must be type-compatible and pass 4D's = test.

NOTE

Times are converted to numbers and thus may by compared with numbers.

.falsey()

.falsey(value : any) : Boolean

Returns the opposite of .truthy().

.getCallStack()

.getCallStack() : Collection

Gets the call stack at any point of execution, even outside of an error handler. The top of the stack will point to the caller of this function. The items in the stack are in the form returned by Get call chainopen in new window.

.instanceof()

.instanceof(value : any; class : 4D.Class) : Boolean

Returns whether value is an instance of class. This differs from OB Instance ofopen in new window in that it will not generate an error if value is not an object. This allows you to test a value of any type on one line.

TIP

.instanceOf() is an alias for this function.

.isArrayPointer()

.isArrayPointer(pointer : Pointer) : Boolean

Returns true if pointer points to an array.

.isCallable()

.isCallable(value : any) : Boolean

Returns true if value is an object which has both .call() and .apply() properties that are functions.

.isCyclic()

.isCyclic(objectOrCollection : Object | Collection) : Boolean

Returns true if objectOrCollection contains a cyclic reference, otherwise false.

.isNumber()

.isNumber(value : any) : Boolean

Returns true if the value type of value is any of 4D’s numeric types.

.isNumericType()

.isNumericType(type : Integer) : Boolean

Returns true if the type is any of 4D’s numeric types.

.max()

.max(value : any { ; …valueN : any }) : any
.max(values : Collection) : any

Returns the maximum of the passed values.

NOTE

All of the values must be of a type that can be compared with the > operator.

.min()

.min(value : any { ; …valueN : any }) : any
.min(values : Collection) : any

Returns the minimum of the passed values.

NOTE

All of the values must be of a type that can be compared with the < operator.

.respondsTo()

.respondsTo(value : Object ; name : Text }) : Boolean

Returns true if value has the property name which is a function.

NOTE

You cannot test computed properties (get/set) with this function.

.sequence()

.sequence(expression : any { ; ….expressionN : any}) : any

Returns the value of the last expression passed to it. expression need not return a value; it can be a command, method call, or class function call with side effects.

This is especially useful when used with formulas, as it gives you the ability to effectively create a multiline formula.

If expression is a Callable, expression.call() is called.

Example

$it.should(\
  "get a dotted key path value"; \
  Formula(This.expect(_.sequence(_.loadConfig(); _.getConfig("foo")))\
    .to.strict.equal("bar")))

.strictEqual()

.strictEqual(value : any; compare : any) : Boolean

This is a convenience function that calls _.equal(value; compare; True).

.truthy()

.truthy(value : any) : Boolean

This is an implementation of the JavaScript truthy test — which is IMHO usually much more useful than 4D’s Boolopen in new window. The results are as follows:

TypeResult
Textfalse if empty, true otherwise
Objectfalse if null, true otherwise
Collectionfalse if null, true otherwise
Booleanvalue
Nullfalse
Undefinedfalse
Numberfalse if 0, true otherwise
Anything elsefalse

.typeName()

.typeName(type : any) : Text

Returns a text description of the given non-array type.

typeResult
Numeric 4D type constant (e.g. Is longint)See the list of type names below
Instance of a classThe instance’s class name
ClassThe class name
Formula"function"
Null"null"
Unknown type constant""

Type constant names

If a numeric type constant is passed, the value returned is the lowercased English constant name without the leading "Is ", except for the cases listed below. For example, if type is Is BLOB, "blob" is returned.

typeResult
Is alpha field"string"
Is integer 64 bits"integer 64"
Is string var"string"
Is variant"any"

.valueIs()

.valueIs(value : any; expectedType : any) : Boolean

Returns whether value’s type is expectedType. expectedType may be a type name or a class. Valid type names are:

blob
boolean
callable (.isCallable() returns true)
class
collection
date
formula (same as function)
function (same as formula)
null
number
object
picture
pointer
string
undefined

Last Updated:
Contributors: Aparajita