How to use the @angular-devkit/core.tags function in @angular-devkit/core

}
        else if (angularVersion.isGreaterThanOrEqualTo(new semver_1.SemVer('6.0.0-rc.0'))
            && !rxjsVersion.isGreaterThanOrEqualTo(new semver_1.SemVer('5.6.0-forward-compat.0'))
            && !rxjsVersion.isGreaterThanOrEqualTo(new semver_1.SemVer('6.0.0-beta.0'))) {
            console.error(core_1.terminal.bold(core_1.terminal.red(core_1.tags.stripIndents `
          This project uses version ${rxjsVersion} of RxJs, which is not supported by Angular v6.
          The official RxJs version that is supported is 5.6.0-forward-compat.0 and greater.

          Please visit the link below to find instructions on how to update RxJs.
          https://docs.google.com/document/d/12nlLt71VLKb-z3YaSGzUfx6mJbc34nsMXtByPUN35cg/edit#
        ` + '\n')));
            process.exit(3);
        }
        else if (angularVersion.isGreaterThanOrEqualTo(new semver_1.SemVer('6.0.0-rc.0'))
            && !rxjsVersion.isGreaterThanOrEqualTo(new semver_1.SemVer('6.0.0-beta.0'))) {
            console.warn(core_1.terminal.bold(core_1.terminal.red(core_1.tags.stripIndents `
          This project uses a temporary compatibility version of RxJs (${rxjsVersion}).

          Please visit the link below to find instructions on how to update RxJs.
          https://docs.google.com/document/d/12nlLt71VLKb-z3YaSGzUfx6mJbc34nsMXtByPUN35cg/edit#
        ` + '\n')));
        }
    }
    static assertTypescriptVersion(projectRoot) {

function validateProjectName(projectName) {
    const errorIndex = getRegExpFailPosition(projectName);
    const unsupportedProjectNames = ['test', 'ember', 'ember-cli', 'vendor', 'app'];
    const packageNameRegex = /^(?:@[a-zA-Z0-9_-]+\/)?[a-zA-Z0-9_-]+$/;
    if (errorIndex !== null) {
        const firstMessage = core_1.tags.oneLine `
    Project name "${projectName}" is not valid. New project names must
    start with a letter, and must contain only alphanumeric characters or dashes.
    When adding a dash the segment after the dash must also start with a letter.
    `;
        const msg = core_1.tags.stripIndent `
    ${firstMessage}
    ${projectName}
    ${Array(errorIndex + 1).join(' ') + '^'}
    `;
        throw new schematics_1.SchematicsException(msg);
    }
    else if (unsupportedProjectNames.indexOf(projectName) !== -1) {
        throw new schematics_1.SchematicsException(`Project name ${JSON.stringify(projectName)} is not a supported name.`);
    }
    else if (!packageNameRegex.test(projectName)) {
        throw new schematics_1.SchematicsException(`Project name ${JSON.stringify(projectName)} is invalid.`);

run(options) {
        const level = options.global ? 'global' : 'local';
        let config = config_1.getWorkspace(level);
        if (options.global && !config) {
            try {
                if (config_1.migrateLegacyGlobalConfig()) {
                    config =
                        config_1.getWorkspace(level);
                    this.logger.info(core_1.tags.oneLine `
            We found a global configuration that was used in Angular CLI 1.
            It has been automatically migrated.`);
                }
            }
            catch (_a) { }
        }
        if (options.value == undefined) {
            if (!config) {
                this.logger.error('No config found.');
                return 1;
            }
            return this.get(config._workspace, options);
        }
        else {
            return this.set(options);
        }

validate(options) {
        if (!options._[0]) {
            this.logger.error(core_1.tags.oneLine `
        The "ng generate" command requires a
        schematic name to be specified.
        For more details, use "ng help".`);
            return false;
        }
        return true;
    }
    run(options) {

const changedChunksStats = json.chunks
        .filter((chunk) => chunk.rendered)
        .map((chunk) => {
        const asset = json.assets.filter((x) => x.name == chunk.files[0])[0];
        const size = asset ? ` ${formatSize(asset.size)}` : '';
        const files = chunk.files.join(', ');
        const names = chunk.names ? ` (${chunk.names.join(', ')})` : '';
        const initial = y(chunk.entry ? '[entry]' : chunk.initial ? '[initial]' : '');
        const flags = ['rendered', 'recorded']
            .map(f => f && chunk[f] ? g(` [${f}]`) : '')
            .join('');
        return `chunk {${y(chunk.id)}} ${g(files)}${names}${size} ${initial}${flags}`;
    });
    const unchangedChunkNumber = json.chunks.length - changedChunksStats.length;
    if (unchangedChunkNumber > 0) {
        return '\n' + rs(core_1.tags.stripIndents `
      Date: ${w(new Date().toISOString())} - Hash: ${w(json.hash)} - Time: ${w('' + json.time)}ms
      ${unchangedChunkNumber} unchanged chunks
      ${changedChunksStats.join('\n')}
      `);
    }
    else {
        return '\n' + rs(core_1.tags.stripIndents `
      Date: ${w(new Date().toISOString())}
      Hash: ${w(json.hash)}
      Time: ${w('' + json.time)}ms
      ${changedChunksStats.join('\n')}
      `);
    }
}
exports.statsToString = statsToString;

workflow.registry.addSmartDefaultProvider('projectName', () => {
            if (this._workspace) {
                try {
                    return this._workspace.getProjectByPath(core_1.normalize(process.cwd()))
                        || this._workspace.getDefaultProjectName();
                }
                catch (e) {
                    if (e instanceof core_1.experimental.workspace.AmbiguousProjectPathException) {
                        this.logger.warn(core_1.tags.oneLine `
              Two or more projects are using identical roots.
              Unable to determine project using current working directory.
              Using default workspace project instead.
            `);
                        return this._workspace.getDefaultProjectName();
                    }
                    throw e;
                }
            }
            return undefined;
        });
        if (options.interactive !== false && process.stdout.isTTY) {

function validateProjectName(projectName) {
    const errorIndex = getRegExpFailPosition(projectName);
    if (errorIndex !== null) {
        const firstMessage = core_1.tags.oneLine `
      Project name "${projectName}" is not valid. New project names must
      start with a letter, and must contain only alphanumeric characters or dashes.
      When adding a dash the segment after the dash must also start with a letter.
    `;
        const msg = core_1.tags.stripIndent `
      ${firstMessage}
      ${projectName}
      ${Array(errorIndex + 1).join(' ') + '^'}
    `;
        throw new schematics_1.SchematicsException(msg);
    }
    else if (unsupportedProjectNames.indexOf(projectName) !== -1) {
        throw new schematics_1.SchematicsException(`Project name "${projectName}" is not a supported name.`);
    }
}
function default_1(options) {

_buildServerConfig(root, projectRoot, options, browserOptions) {
        const systemRoot = core_1.getSystemPath(root);
        if (options.disableHostCheck) {
            this.context.logger.warn(core_1.tags.oneLine `
        WARNING: Running a server with --disable-host-check is a security risk.
        See https://medium.com/webpack/webpack-dev-server-middleware-security-issues-1489d950874a
        for more information.
      `);
        }
        const servePath = this._buildServePath(options, browserOptions);
        const config = {
            host: options.host,
            port: options.port,
            headers: { 'Access-Control-Allow-Origin': '*' },
            historyApiFallback: {
                index: `${servePath}/${path.basename(browserOptions.index)}`,
                disableDotRule: true,
                htmlAcceptHeaders: ['text/html', 'application/xhtml+xml'],
            },
            stats: false,

function usage(exitCode = 0) {
    logger.info(core_1.tags.stripIndent `
    schematics [CollectionName:]SchematicName [options, ...]

    By default, if the collection name is not specified, use the internal collection provided
    by the Schematics CLI.

    Options:
        --debug             Debug mode. This is true by default if the collection is a relative
                            path (in that case, turn off with --debug=false).
        --dry-run           Do not output anything, but instead just show what actions would be
                            performed. Default to true if debug is also true.
        --force             Force overwriting files that would otherwise be an error.
        --list-schematics   List all schematics from the collection, by name.
        --verbose           Show more information.

        --help              Show this message.

async validateScope(scope) {
        switch (scope === undefined ? this.description.scope : scope) {
            case interface_1.CommandScope.OutProject:
                if (this.workspace.configFile) {
                    this.logger.fatal(core_1.tags.oneLine `
            The ${this.description.name} command requires to be run outside of a project, but a
            project definition was found at "${path.join(this.workspace.root, this.workspace.configFile)}".
          `);
                    throw 1;
                }
                break;
            case interface_1.CommandScope.InProject:
                if (!this.workspace.configFile || config_1.getWorkspace('local') === null) {
                    this.logger.fatal(core_1.tags.oneLine `
            The ${this.description.name} command requires to be run in an Angular project, but a
            project definition could not be found.
          `);
                    throw 1;
                }
                break;
            case interface_1.CommandScope.Everywhere: