Fix Firebase issue on {NS} 8.2

firebase-build-gradle.js

var path = require("path");
var fs = require("fs");

module.exports = function($logger, $projectData) {
    let buildGradleContent;

    function patchNode(node, check, content = check)
    {
        const originalDepNode = buildGradleContent.match(
            new RegExp(node + " {[\\s\\S]*?}", "gi")
        ).shift();

        if (!originalDepNode || originalDepNode.indexOf(check) > 0) {
            return;
        }

        const endNode = originalDepNode.indexOf("}", 0);
        const modDepNode = originalDepNode.substring(0, endNode - 1)
            +  '	    ' + content + '\n'
            + originalDepNode.substring(endNode - 1);

        buildGradleContent = buildGradleContent.replace(
            originalDepNode,
            modDepNode
        );
    }

    return new Promise(function(resolve, reject) {
        $logger.info("Configure firebase");
        let projectBuildGradlePath = path.join($projectData.platformsDir, "android", "build.gradle");

        if (fs.existsSync(projectBuildGradlePath)) {
            buildGradleContent = fs.readFileSync(projectBuildGradlePath).toString();

            patchNode(
                "repositories",
                "google()"
            );

            patchNode(
                "repositories",
                "https://dl.bintray.com/android/android-tools",
                'maven { url "https://dl.bintray.com/android/android-tools" }'
            );

            patchNode(
                "dependencies",
                "com.google.firebase:firebase-crashlytics-gradle",
                'classpath "com.google.firebase:firebase-crashlytics-gradle:2.3.0"'
            );

            // Remove maybe old google services
            buildGradleContent = buildGradleContent.replace(
                /classpath ('|")com\.google\.gms:google-services:\d+\.\d+\.\d+('|")/, ''
            );

            patchNode(
                "dependencies",
                "com.google.gms:google-services",
                'classpath "com.google.gms:google-services:4.3.4"'
            );

            fs.writeFileSync(projectBuildGradlePath, buildGradleContent);
        }

        let projectAppBuildGradlePath = path.join($projectData.platformsDir, "android", "app", "build.gradle");
        if (fs.existsSync(projectAppBuildGradlePath)) {
          let appBuildGradleContent = fs.readFileSync(projectAppBuildGradlePath).toString();
          if (appBuildGradleContent.indexOf("buildMetadata.finalizedBy(copyMetadata)") === -1) {
            appBuildGradleContent = appBuildGradleContent.replace(
                "ensureMetadataOutDir.finalizedBy(buildMetadata)",
                "ensureMetadataOutDir.finalizedBy(buildMetadata)\n\t\tbuildMetadata.finalizedBy(copyMetadata)"
            );
            appBuildGradleContent += `
task copyMetadata {
  doFirst {
      // before tns-android 5.2.0 its gradle version didn't have this method implemented, so pri
      android.applicationVariants.all { variant ->
          if (variant.buildType.name == project.selectedBuildType) {
              def task
              if (variant.metaClass.respondsTo(variant, "getMergeAssetsProvider")) {
                  def provider = variant.getMergeAssetsProvider()
                  task = provider.get();
              } else {
                  // fallback for older android gradle plugin versions
                  task = variant.getMergeAssets()
              }
              for (File file : task.getOutputs().getFiles()) {
                  if (!file.getPath().contains("/incremental/")) {
                      project.ext.mergedAssetsOutputPath = file.getPath()
                  }
              }
          }
      }
  }
  doLast {
    copy {
      if (!project.mergedAssetsOutputPath) {
        // mergedAssetsOutputPath not found fallback to the default value for android gradle plugin 3.4.0
        project.ext.mergedAssetsOutputPath = "$projectDir/build/intermediates/assets/" + project.selectedBuildType + "/out"
      }
      from "$projectDir/src/main/assets/metadata"
      into project.mergedAssetsOutputPath + "/metadata"
    }
  }
}`;
            fs.writeFileSync(projectAppBuildGradlePath, appBuildGradleContent);
          }
        }

        resolve();
    });
};

¿Cómo se usa? saludos!