approvals/lib/FileApprover.ts

Approval Tests Library - Capturing Human Intelligence

import fs from "fs";
import { Config } from "./config";
import { Namer } from "./Core/Namer";
import { Writer } from "./Core/Writer";
import { Reporter } from "./Core/Reporter";
import { ReporterLoader } from "./Reporting/ReporterFactory";
import { yellowText } from "./Utilities/ConsoleUtils";
import { ApprovedFileLog } from "./Logs/ApprovedFileLog";
import { FailedFileLog } from "./Logs/FailedFileLog";

function normalizeLineEndings(value: string): string {
  return value.replace(/(?:\r\n|\r|\n)/g, "\n");
}

export class FileApprover {
  static verify(
    namer: Namer,
    writer: Writer,
    reporterFactory: ReporterLoader,
    options?: Partial<Config>,
  ): void {
    if (!namer || !writer || !reporterFactory) {
      const missing = [
        !namer ? "namer" : null,
        !writer ? "writer" : null,
        !reporterFactory ? "reporterFactory" : null,
      ]
        .filter(Boolean)
        .join(", ");
      throw new Error(`Missing required arguments: ${missing}.`);
    }
    if (!options) {
      options = {};
    }

    const approvedFileName = namer.getApprovedFile(writer.getFileExtension());
    const receivedFileName = namer.getReceivedFile(writer.getFileExtension());
    FailedFileLog.touch();
    ApprovedFileLog.log(approvedFileName);
    writer.write(receivedFileName);

    if (options.forceApproveAll) {
      console.log(yellowText(`WARNING: Force approving: ${approvedFileName}`));
      writer.write(approvedFileName);
    }

    const selectFirstCompatibleReporter = (): Reporter => {
      const allReporters = reporterFactory();
      const reporter = allReporters.find((reporter) =>
        reporter.canReportOn(receivedFileName),
      );
      if (!reporter) {
        throw new Error(
          `No compatible reporter found in configured list [${allReporters.map((r) => r.name).join(", ")}] for: ${receivedFileName}`,
        );
      }
      return reporter;
    };

    const throwReporterError = (msg: string): never => {
      FailedFileLog.log(approvedFileName, receivedFileName);
      const reporter = selectFirstCompatibleReporter();
      try {
        reporter.report(approvedFileName, receivedFileName, options);
      } catch (ex) {
        const reporterError = `Error raised by reporter [${reporter.name}]: ${ex}`;
        throw new Error(
          `${reporterError}\n${msg}\nApproved: ${approvedFileName}\nReceived: ${receivedFileName}`,
        );
      }
      throw new Error(msg);
    };

    if (!fs.existsSync(approvedFileName)) {
      throwReporterError(`Approved file does not exist: ${approvedFileName}`);
    }

    let approvedFileContents = fs.readFileSync(approvedFileName, "utf8") || "";
    let receivedFileContents = fs.readFileSync(receivedFileName, "utf8") || "";

    if (options.stripBOM) {
      approvedFileContents = approvedFileContents.replace(/^\uFEFF/, "");
      receivedFileContents = receivedFileContents.replace(/^\uFEFF/, "");
    }

    if (
      options.failOnLineEndingDifferences &&
      approvedFileContents !== receivedFileContents
    ) {
      throwReporterError("Files do not match.");
    }

    const approvedFileBufferNormalized =
      normalizeLineEndings(approvedFileContents);
    const receivedFileBufferNormalized =
      normalizeLineEndings(receivedFileContents);

    if (approvedFileBufferNormalized !== receivedFileBufferNormalized) {
      throwReporterError("Files do not match.");
    }

    // Delete the received file
    fs.unlinkSync(receivedFileName);

    (process.emit as Function)("approvalFileApproved", approvedFileName);
  }
}

export function verify(
  namer: Namer,
  writer: Writer,
  reporterFactory: () => Reporter[],
  options?: Partial<Config>,
): void {
  FileApprover.verify(namer, writer, reporterFactory, options);
}