Join-like methods

[Dam-Buty]

The use case is to be able to "join" the rows from a CSV to the rows from another array of objects, using a column of each collection to determine identity.

For example :

const enrichedRows = await withCSV("").columns(["id"]).leftJoin(arrayOfObjects, { on: { left: "id", right: "uid" } })

// Alternative with a callback
const enrichedRows = await withCSV("").columns(["id"]).leftJoinBy(arrayOfObjects, (row, arrayOfObjects) => {
  return arrayOfObjects.find(object => object.uid === row.id)
})

// Also innerJoin and rightJoin variants

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Another use case is to be able to map the value of a column to a line from a correspondance table :

const categoryNames = {
  FSN: "Fashion",
  SPT: "Sport",
  RCK: "Rock'n'roll baby"
}

const enrichedRows = await withCSV("").columns(["id", "name", "categoryId"]).mapKey("categoryId", categoryNames)

// Also mapKeyBy variant that takes a callback