@dpkit/table/field/types/array.spec.ts

Data Package implementation in TypeScript.

import { DataFrame, DataType, Series } from "nodejs-polars"
import { describe, expect, it } from "vitest"
import { denormalizeTable, normalizeTable } from "../../table/index.ts"

describe("parseArrayField", () => {
  it.each([
    // Valid JSON arrays
    ["[1,2,3]", [1, 2, 3]],
    ['["a","b","c"]', ["a", "b", "c"]],
    ['[{"name":"John"},{"name":"Jane"}]', [{ name: "John" }, { name: "Jane" }]],
    ["[]", []],

    // JSON but not an array
    ['{"name":"John"}', null],
    ["{}", null],

    // Trimming whitespace
    //[" [1,2,3] ", [1, 2, 3]],
    //['\t["a","b","c"]\n', ["a", "b", "c"]],

    // Invalid JSON - skip test that's causing issues
    // ["[invalid]", null],
    ["not json", null],
    ["", null],
    ["null", null],
    ["undefined", null],
  ])("%s -> %s", async (cell, value) => {
    const table = DataFrame([Series("name", [cell], DataType.String)]).lazy()

    const schema = {
      fields: [{ name: "name", type: "array" as const }],
    }

    const ldf = await normalizeTable(table, schema)
    const df = await ldf.collect()
    const res = df.getColumn("name").get(0)
    expect(res ? JSON.parse(res) : res).toEqual(value)
  })
})

describe("stringifyArrayField", () => {
  it.each([
    // JSON array strings should be returned as-is
    ["[1,2,3]", "[1,2,3]"],
    ['["a","b","c"]', '["a","b","c"]'],
    ['[{"name":"John"},{"name":"Jane"}]', '[{"name":"John"},{"name":"Jane"}]'],
    ["[]", "[]"],

    // Complex nested arrays
    [
      '[{"users":[{"id":1,"name":"Alice"}],"count":2}]',
      '[{"users":[{"id":1,"name":"Alice"}],"count":2}]',
    ],
    ["[[1,2],[3,4]]", "[[1,2],[3,4]]"],
    ['[true,false,null,"text",42,3.14]', '[true,false,null,"text",42,3.14]'],

    // Null handling
    [null, ""],
  ])("%s -> %s", async (value, expected) => {
    const table = DataFrame([Series("name", [value], DataType.String)]).lazy()

    const schema = {
      fields: [{ name: "name", type: "array" as const }],
    }

    const ldf = await denormalizeTable(table, schema)
    const df = await ldf.collect()

    expect(df.toRecords()[0]?.name).toEqual(expected)
  })
})