oriju

#OriJu

##What's that?

It's reduce() for binary or 'normal' trees.

##What do one use that for?

It's intended to be used to traverse and transform trees in a functional fashion as an alternative to visitor pattern and such.

##Example?

``typescript
import {Tree} from "oriju";

// filter in the format of a popular UI library
const filter = {
logic: "and",
filters: [
{
logic: "or",
filters: [
{
operator: "eq",
field: "position",
value: "QA Engineer"
},
{
operator: "eq",
field: "position",
value: "UX Engineer"
}
]
},
{
operator: "eq",
field: "age",
value: "20"
}
]
};

// translating it to elasticsearch QueryDSL
Tree.from(filter, "filters").fold(
(acc, node)=>({
bool: {
[node.logic == "or" ? "should" : "must"]: acc
}}),
(leaf)=>({
// for simplicity, assuming operator to be always "eq"
term: {[leaf.field]: leaf.value}
})
);
``