# Mutate transformation

{ mutate: ... }

mutate is used to calculate a new column based on the available data. transmute does the same thing, except it throws away all columns other than the just calculated ones.

# Instructions

# Usage

The Object passed to mutate or transmute will have the new column names as keys, and a Function to calculate these new columns as value. The Function will be passed the current row, row index, previous row and next row:

{ mutate: { <column name>: (row, i, prevRow, nextRow) => { /* Function body */ } } }

<vgg-data
  :data="{ a: [1, 2, 3, 4] }"
  :transform="{ mutate: { aSquared: (row, i, prevRow, nextRow) => row.a * row.a } }"
>

  <!-- Data scope: { a: [1, 2, 3, 4], aSquared: [1, 4, 9, 16] } -->

</vgg-data>

Here the same thing, but with transmute:

<vgg-data
  :data="{ a: [1, 2, 3, 4] }"
  :transform="{ transmute: { aSquared: (row, i, prevRow, nextRow) => row.a * row.a } }"
>

  <!-- Data scope: { aSquared: [1, 4, 9, 16] } -->

</vgg-data>