Lazy.js如何通过两个字段选择不同的（uniq）

Question

We are using Lazy.js.

If I have selected one field, I know I can use the uniq(fieldName) function to get distinct results.

For example:

var uniqueValues = Lazy(someArray)
                   .map(function (e) { return e.fieldName })
                   .uniq()
                   .value();

How do you do the same operation on two fields?

This is what I tried:

var uniqueValues = Lazy(someArray)
                   .map(function (e) return { FieldName1 : e.fieldName1, FieldName2 : e.fieldName2 })
                   .uniq();
                   .value();

But it's not making it distinct by both fields.

Answer 1

uniq can take in a function parameter which can return which specific field to run the distinct by.

For example:

 var uniqueValues = Lazy(someArray)
        .map(function (e) return { FieldName1 : e.fieldName1, FieldName2 : e.fieldName2 })
        .uniq(function (e) { return e.FieldName1 })
        .value();