anomalyco_opencode/packages/codemode/test/callbacks.test.ts

import { describe, expect, test } from "bun:test"
import { Effect, Schema } from "effect"
import { CodeMode, Tool } from "../src/index.js"

// Callback acceptance is one gate shared by array methods, sort, string replacers,
// Array.from mappers, Map/Set/URLSearchParams forEach, and promise reactions:
// interpreter functions, coercion/URI builtins, resolver capabilities, and built-in
// method references are callable; tools and other opaque callables get a wrap hint.
const run = (code: string) => Effect.runPromise(CodeMode.execute({ code, tools: {} }))
const value = async (code: string) => {
  const result = await run(code)
  if (!result.ok) throw new Error(`expected success, got ${result.error.kind}: ${result.error.message}`)
  return result.value
}
const error = async (code: string) => {
  const result = await run(code)
  if (result.ok) throw new Error(`expected failure, got value ${JSON.stringify(result.value)}`)
  return result.error
}
const logsOf = async (code: string) => {
  const result = await run(code)
  if (!result.ok) throw new Error(`expected success, got ${result.error.kind}: ${result.error.message}`)
  return result.logs ?? []
}

const echo = Tool.make({
  description: "Echo the input",
  input: Schema.Struct({ id: Schema.Number }),
  output: Schema.Number,
  run: (input: { id: number }) => Effect.succeed(input.id),
})
const withTool = (code: string) => Effect.runPromise(CodeMode.make({ tools: { host: { echo } } }).execute(code))
const toolError = async (code: string) => {
  const result = await withTool(code)
  if (result.ok) throw new Error(`expected failure, got value ${JSON.stringify(result.value)}`)
  return result.error
}

describe("built-in method references as callbacks", () => {
  test("map accepts Math methods", async () => {
    expect(await value(`return [-1, 2, -3].map(Math.abs)`)).toEqual([1, 2, 3])
    expect(await value(`return [1.5, 2.7].map(Math.floor)`)).toEqual([1, 2])
  })

  test("map(JSON.stringify) matches JS: the index replacer and array space are ignored", async () => {
    expect(await value(`return [{ a: 1 }, [2]].map(JSON.stringify)`)).toEqual(['{"a":1}', "[2]"])
  })

  test("map(Number.parseInt) reproduces the JS radix footgun", async () => {
    // parseInt("2", 1) is NaN in real JS; NaN serializes to null at the result boundary.
    expect(await value(`return ["1", "2"].map(Number.parseInt)`)).toEqual([1, null])
  })

  test("filter and find accept built-in predicates", async () => {
    expect(await value(`return [0, 1, NaN, 2].filter(Number.isInteger)`)).toEqual([0, 1, 2])
    expect(await value(`return [1.5, 3, 2.5].find(Number.isInteger)`)).toBe(3)
  })

  test("forEach(console.log) captures one log line per element", async () => {
    const logs = await logsOf(`["a", "b"].forEach(console.log); return null`)
    expect(logs).toHaveLength(2)
    expect(logs[0]).toContain("a")
    expect(logs[1]).toContain("b")
  })

  test("intrinsic method references keep their receiver, unlike detached JS methods", async () => {
    expect(await value(`return ["a", "z"].filter("abc".includes)`)).toEqual(["a"])
  })

  test("promise reactions accept built-in references", async () => {
    expect(await value(`return await Promise.resolve(-5).then(Math.abs)`)).toBe(5)
    const logs = await logsOf(`await Promise.resolve("done").then(console.log); return null`)
    expect(logs).toHaveLength(1)
    expect(logs[0]).toContain("done")
  })
})

describe("sort accepts the unified callback set", () => {
  test("sort and toSorted take built-in comparators", async () => {
    expect(await value(`return [0, 1, 0].sort(Boolean)`)).toEqual([0, 0, 1])
    expect(await value(`return [0, 1, 0].toSorted(Boolean)`)).toEqual([0, 0, 1])
  })

  test("a non-callable comparator is rejected", async () => {
    expect((await error(`return [2, 1].sort(42)`)).message).toContain("Array.sort expects a function callback")
    expect((await error(`return [2, 1].toSorted(42)`)).message).toContain("Array.toSorted expects a function callback")
  })
})

describe("Array.from mapper", () => {
  test("maps with (value, index) over arrays, strings, and Sets", async () => {
    expect(await value(`return Array.from([1, 2, 3], (x) => x * 2)`)).toEqual([2, 4, 6])
    expect(await value(`return Array.from("ab", (c, i) => c + i)`)).toEqual(["a0", "b1"])
    expect(await value(`return Array.from(new Set([1, 2]), (x) => x * 10)`)).toEqual([10, 20])
  })

  test("accepts coercion builtins and an explicit undefined mapper", async () => {
    expect(await value(`return Array.from(["5", "7"], Number)`)).toEqual([5, 7])
    expect(await value(`return Array.from([1, 2], undefined)`)).toEqual([1, 2])
  })

  test("rejects a non-callable mapper and a thisArg", async () => {
    expect((await error(`return Array.from([1], 42)`)).message).toContain("Array.from expects a function callback")
    const diagnostic = await error(`return Array.from([1], (x) => x, {})`)
    expect(diagnostic.kind).toBe("UnsupportedSyntax")
    expect(diagnostic.message).toContain("thisArg")
  })
})

describe("thisArg is rejected loudly", () => {
  test("array iteration methods reject a thisArg and allow explicit undefined", async () => {
    const diagnostic = await error(`return [1, 2].map((x) => x, {})`)
    expect(diagnostic.kind).toBe("UnsupportedSyntax")
    expect(diagnostic.message).toContain("Array.map does not support a thisArg")
    expect((await error(`return [1].forEach((x) => x, "self")`)).message).toContain("thisArg")
    expect(await value(`return [1, 2].map((x) => x, undefined)`)).toEqual([1, 2])
  })

  test("Map, Set, and URLSearchParams forEach reject a thisArg", async () => {
    expect((await error(`new Map([["a", 1]]).forEach(() => {}, {}); return null`)).message).toContain("Map.forEach")
    expect((await error(`new Set([1]).forEach(() => {}, {}); return null`)).message).toContain("Set.forEach")
    expect((await error(`new URLSearchParams("a=1").forEach(() => {}, {}); return null`)).message).toContain(
      "URLSearchParams.forEach",
    )
  })
})

describe("still-rejected callables get the wrap hint", () => {
  test("tool references as callbacks suggest an arrow wrapper", async () => {
    const diagnostic = await toolError(`return [1, 2].map(tools.host.echo)`)
    expect(diagnostic.message).toContain("wrap it in an arrow function")
    expect(await withTool(`return await Promise.all([1, 2].map((id) => tools.host.echo({ id })))`)).toMatchObject({
      ok: true,
      value: [1, 2],
    })
  })

  test("Error constructors and Promise statics as callbacks suggest an arrow wrapper", async () => {
    expect((await error(`return [1].map(Error)`)).message).toContain("wrap it in an arrow function")
    expect((await error(`return [1].map(Promise.resolve)`)).message).toContain("wrap it in an arrow function")
  })

  test("string replacers reject opaque callables with the wrap hint, not a type error", async () => {
    const diagnostic = await toolError(`return "abc".replace(/b/, tools.host.echo)`)
    expect(diagnostic.message).toContain("wrap it in an arrow function")
    expect(diagnostic.message).not.toContain("argument 2")
  })

  test("built-in references work as replacers", async () => {
    // Like real JS: JSON.stringify(match, offset, string) quotes the match.
    expect(await value(`return "abc".replace(/b/, JSON.stringify)`)).toBe('a"b"c')
    // Math methods stay strict about consumed arguments: a match string is not coerced.
    expect((await error(`return "3.7".replace(/\\d\\.\\d/, Math.floor)`)).message).toContain(
      "Math.floor expects number arguments",
    )
  })

  test("non-callables still get the plain callback error", async () => {
    expect((await error(`return [1].map(42)`)).message).toContain("Array.map expects a function callback")
  })
})