bun.sh/test/js/node/module/sourcemap.test.js

const { test, expect } = require("bun:test");
const { SourceMap } = require("node:module");

test("SourceMap class exists", () => {
  expect(SourceMap).toBeDefined();
  expect(typeof SourceMap).toBe("function");
  expect(SourceMap.name).toBe("SourceMap");
});

test("SourceMap constructor requires payload", () => {
  expect(() => {
    new SourceMap();
  }).toThrowErrorMatchingInlineSnapshot(`"The "payload" argument must be of type object. Received undefined"`);
});

test("SourceMap payload must be an object", () => {
  expect(() => {
    new SourceMap("not an object");
  }).toThrowErrorMatchingInlineSnapshot(
    `"The "payload" argument must be of type object. Received type string ('not an object')"`,
  );
});

test("SourceMap instance has expected methods", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  });

  expect(typeof sourceMap.findOrigin).toBe("function");
  expect(typeof sourceMap.findEntry).toBe("function");
  expect(sourceMap.findOrigin.length).toBe(2);
  expect(sourceMap.findEntry.length).toBe(2);
});

test("SourceMap payload getter", () => {
  const payload = {
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  };
  const sourceMap = new SourceMap(payload);

  expect(sourceMap.payload).toBe(payload);
});

test("SourceMap lineLengths getter", () => {
  const payload = {
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  };
  const lineLengths = [10, 20, 30];
  const sourceMap = new SourceMap(payload, { lineLengths });

  expect(sourceMap.lineLengths).toBe(lineLengths);
});

test("SourceMap lineLengths undefined when not provided", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  });

  expect(sourceMap.lineLengths).toBeUndefined();
});
test("SourceMap findEntry returns mapping data", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  });
  const result = sourceMap.findEntry(0, 0);

  expect(result).toMatchInlineSnapshot(`
    {
      "generatedColumn": 0,
      "generatedLine": 0,
      "name": undefined,
      "originalColumn": 0,
      "originalLine": 0,
      "originalSource": "test.js",
    }
  `);
});

test("SourceMap findOrigin returns origin data", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  });
  const result = sourceMap.findOrigin(0, 0);

  expect(result).toMatchInlineSnapshot(`
    {
      "column": 0,
      "fileName": "test.js",
      "line": 0,
      "name": undefined,
    }
  `);
});

test("SourceMap with names returns name property correctly", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    names: ["myFunction", "myVariable"],
    mappings: "AAAAA,CAACC", // Both segments reference names
  });

  const result = sourceMap.findEntry(0, 0);
  const resultWithName = sourceMap.findEntry(0, 6);
  expect(result).toMatchInlineSnapshot(`
    {
      "generatedColumn": 0,
      "generatedLine": 0,
      "name": "myFunction",
      "originalColumn": 0,
      "originalLine": 0,
      "originalSource": "test.js",
    }
  `);
  expect(resultWithName).toMatchInlineSnapshot(`
    {
      "generatedColumn": 1,
      "generatedLine": 0,
      "name": "myVariable",
      "originalColumn": 1,
      "originalLine": 0,
      "originalSource": "test.js",
    }
  `);
});

test("SourceMap without names has undefined name property", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    mappings: "AAAA",
  });

  const result = sourceMap.findEntry(0, 0);
  expect(result).toMatchInlineSnapshot(`
    {
      "generatedColumn": 0,
      "generatedLine": 0,
      "name": undefined,
      "originalColumn": 0,
      "originalLine": 0,
      "originalSource": "test.js",
    }
  `);
});

test("SourceMap with invalid name index has undefined name property", () => {
  const sourceMap = new SourceMap({
    version: 3,
    sources: ["test.js"],
    mappings: "AAAAA,CAACC", // Both segments reference names
  });

  const result = sourceMap.findEntry(0, 0);
  expect(result).toMatchInlineSnapshot(`
    {
      "generatedColumn": 0,
      "generatedLine": 0,
      "name": undefined,
      "originalColumn": 0,
      "originalLine": 0,
      "originalSource": "test.js",
    }
  `);
});