Version 2.x

This function declares that methods with a certain name should be chained in the reversed inheritance order (the last method runs first).

Description

dcl.chainBefore() sets the before chaining rule for a method. It takes two parameters:

• Ctr - the constructor function created by dcl().
• name - the method name to be chained in Ctr’s prototype.

Following rules should be followed:

• It is impossible to “unchain” a chained method.
• It is impossible to change a chained method once it was set from “before” to “after” or in the opposite direction.
• Chaining should be declared only for base-less “classes”.
• It is an error to mix “classes” with different chaining rules for the same method.
• It is possible to declare chaining for a method without actually declaring the method.

The function returns true, if it was able to define a required chaining, false, if a constructor was not defined by dcl(), and throws an error, if a chaining conflict was detected.

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var A = dcl({
  ...
  method: function (...) {...},
  ...
});
dcl.chainBefore(A, "method");

Notes

Chaining using “before” is frequently used for destructors or similar methods.

Implementation

It is implemented in terms of dcl.chainWith() and dcl.weaveBefore:

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dcl.chainBefore = function (Ctr, name) {
  return dcl.chainWith(Ctr, name, dcl.weaveBefore);
};