test.js

const test = require("tape")
const merge = require("./index")

test("SET", (t) => {
  t.plan(2)

  t.deepEqual(
    merge({ x: 42 }),
    {
      UpdateExpression: "SET x = :x",
      ExpressionAttributeValues: { ':x': 42 }
    }
  )

  t.deepEqual(
    merge({ x: { y: "foo", z: { w: 42 } }, q: 0 }),
    {
      UpdateExpression: "SET x.y = :x_y, x.z.w = :x_z_w, q = :q",
      ExpressionAttributeValues: { ":x_y": "foo", ":x_z_w": 42, ":q": 0 }
    }
  )
})

test("Combination", (t) => {
  t.plan(1)

  t.deepEqual(
    merge({ x: { y: [1, 2], z: "x" }, q: 10 }),
    {
      UpdateExpression: "SET x.z = :x_z, q = :q ADD x.y :x_y0, x.y :x_y1",
      ExpressionAttributeValues: { ":x_z": "x", ":q": 10, ":x_y0": 1, ":x_y1": 2 }
    }
  )
})


test("Functions", (t) => {
  t.plan(1)

  t.deepEqual(
    merge({ x: { y: () => "foo", z: "x" }, q: 10 }),
    {
      UpdateExpression: "SET x.y = :x_y, x.z = :x_z, q = :q",
      ExpressionAttributeValues: { ":x_y": "foo", ":q": 10, ":x_z": "x" }
    }
  )
})

test("Null values should be deleted", (t) => {
  t.plan(3)

  t.deepEqual(
    merge({ x: null }),
    {
      UpdateExpression: "DELETE x",
      ExpressionAttributeValues: {}
    }
  )

  t.deepEqual(
    merge({ x: null, y: "foo" }),
    {
      UpdateExpression: "SET y = :y DELETE x",
      ExpressionAttributeValues: { ":y": "foo" }
    }
  )


  t.deepEqual(
    merge({ x: { y: null, z: { w: 42 } }, q: 0 }),
    {
      UpdateExpression: "SET x.z.w = :x_z_w, q = :q DELETE x.y",
      ExpressionAttributeValues: { ":x_z_w": 42, ":q": 0 }
    }
  )
})

test("Undefineds should be left alone", (t) => {
  t.plan(2)

  t.deepEqual(
    merge({ x: undefined }),
    { UpdateExpression: "", ExpressionAttributeValues: {} }
  )

  t.deepEqual(
    merge({ x: { y: undefined, z: { w: 42 } }, q: 0 }),
    {
      UpdateExpression: "SET x.z.w = :x_z_w, q = :q",
      ExpressionAttributeValues: { ":x_z_w": 42, ":q": 0 }
    }
  )
})

test("Booleans", (t) => {
  t.plan(1)

  t.deepEqual(
    merge({ x: false }),
    {
      UpdateExpression: "SET x = :x",
      ExpressionAttributeValues: { ":x": false }
    }
  )
})