parser-api.js

"use strict";

const prettier = require("prettier-local");
const runPrettier = require("../runPrettier.js");

test("allows custom parser provided as object", () => {
  const output = prettier.format("1", {
    parser(text) {
      expect(text).toBe("1");
      return {
        type: "Literal",
        value: 2,
        raw: "2",
      };
    },
  });
  expect(output).toBe("2");
});

test("allows usage of prettier's supported parsers", () => {
  const output = prettier.format("foo ( )", {
    parser(text, parsers) {
      expect(typeof parsers.babel).toBe("function");
      const ast = parsers.babel(text);
      ast.program.body[0].expression.callee.name = "bar";
      return ast;
    },
  });
  expect(output).toBe("bar();\n");
});

test("parsers should allow omit optional arguments", () => {
  let parsers;
  try {
    prettier.format("{}", {
      parser(text, builtinParsers) {
        parsers = builtinParsers;
      },
    });
  } catch {
    // noop
  }

  expect(typeof parsers.babel).toBe("function");
  const code = {
    graphql: "type A {hero: Character}",
    default: "{}",
  };
  for (const [name, parse] of Object.entries(parsers)) {
    // Private parser should not be used by users
    if (name.startsWith("__")) {
      continue;
    }

    expect(() => parse(code[name] || code.default)).not.toThrow();
  }
});

test("allows add empty `trailingComments` array", () => {
  const output = prettier.format("(foo /* comment */)( )", {
    parser(text, parsers) {
      const ast = parsers.babel(text);

      // This may happens in this use case https://github.com/prettier/prettier/pull/5497#issuecomment-439841965
      // Simply simulate it
      const callExpression = ast.program.body[0].expression;
      callExpression.extra = { parenthesized: true };
      callExpression.trailingComments = [];

      return ast;
    },
  });
  expect(output).toBe("foo(/* comment */);\n");
});

describe("allows passing a string to resolve a parser", () => {
  runPrettier("./custom-parsers/", [
    "--end-of-line",
    "lf",
    "./custom-rename-input.js",
    "--parser",
    "./custom-rename-parser",
  ]).test({
    status: 0,
  });
});