my-idlers/node_modules/collect.js/docs/api/macro.md

macro()

The macro method lets you register custom methods

collect().macro('uppercase', function () {
  return this.map(item => item.toUpperCase());
});

const collection = collect(['a', 'b', 'c']);

collection.uppercase();

collection.all();

// ['A', 'B', 'C']

Note that the macro method returns undefined, and therefore it is not possible to use it within a chain of methods.

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