cli-testing-library/src/pretty-cli.ts

Simple and complete CLI testing utilities that encourage good testing practices.

import sliceAnsi from "slice-ansi";
import { getUserCodeFrame } from "./get-user-code-frame";
import type { TestInstance } from "./types";

function prettyCLI(testInstance: TestInstance, maxLength?: number) {
  if (typeof maxLength !== "number") {
    maxLength =
      (typeof process !== "undefined" &&
        Number(process.env.DEBUG_PRINT_LIMIT)) ||
      7000;
  }

  if (maxLength === 0) {
    return "";
  }

  if (!("stdoutArr" in testInstance && "stderrArr" in testInstance)) {
    throw new TypeError(`Expected an instance but got ${testInstance}`);
  }

  const outStr = testInstance.getStdallStr();

  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
  return maxLength !== undefined && outStr.length > maxLength
    ? sliceAnsi(outStr, 0, maxLength)
    : outStr;
}

const logCLI = (...args: Parameters<typeof prettyCLI>) => {
  const userCodeFrame = getUserCodeFrame();
  if (userCodeFrame) {
    process.stdout.write(`${prettyCLI(...args)}\n\n${userCodeFrame}`);
  } else {
    process.stdout.write(prettyCLI(...args));
  }
};

export { prettyCLI, logCLI };