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arangodbaql

Arangodb array reduce

Given the following:

LET replacements = [
  ["foo", "bar"],
  ["bar", "baz"]
]

LET title = "foo"

// JS CODE
// title = replacements.reduce((acc, r) => r.replace(acc[0], acc[1]), title);
// or
// for (const r of replacements) {
//   title = title.replace(r[0], r[1]);
// }

RETURN title

How is the logic I described with JS possible to implement in aql?

I can't seem to get FOR loops to work without returning something, and LET itself seems not to allow further reassignment.

Solution

  • This could be a case for a user function.

    In arangosh:

    127.0.0.1:8529@_system> require("@arangodb/aql/functions").register(
    "MYFUNC::REPLACEEQ", 
    function (replacements, title) {
        return replacements.reduce(
                (t, r) => t.replace(r[0], r[1]),
                title
        );
    }
);

    The AQL-Query:

    LET replacements = [
  ["foo", "bar"],
  ["bar", "baz"]
]

RETURN MYFUNC::REPLACEEQ(replacements, "foo")
// => ["baz"]