How to use the cspell-lib.validateText function in cspell-lib

export async function validateTextDocumentAsync(textDocument: TextDocument, options: CSpellUserSettings): Promise> {
    const { diagnosticLevel = DiagnosticSeverity.Information.toString() } = options;
    const severity = diagSeverityMap.get(diagnosticLevel.toLowerCase()) || DiagnosticSeverity.Information;
    const limit = (options.checkLimit || defaultCheckLimit) * 1024;
    const text = textDocument.getText().slice(0, limit);
    const diags = genSequence(await validateText(text, options))
        // Convert the offset into a position
        .map(offsetWord => ({...offsetWord, position: textDocument.positionAt(offsetWord.offset) }))
        // Calculate the range
        .map(word => ({
            ...word,
            range: {
                start: word.position,
                end: ({...word.position, character: word.position.character + word.text.length })
            }
        }))
        // Convert it to a Diagnostic
        .map(({text, range}) => ({
            severity,
            range: range,
            message: `"${text}": Unknown word.`,
            source: diagSource

languageId: cfg.options.languageId || undefined,
            language: cfg.local || undefined,
        });

        const { filename, text } = fileInfo;
        const info = calcFinalConfigInfo(configInfo, settingsFromCommandLine, filename, text);
        const config = info.configInfo.config;
        const source = info.configInfo.source;
        cfg.debug(`Filename: ${filename}, Extension: ${path.extname(filename)}, LanguageIds: ${info.languageIds.toString()}`);

        if (!info.configInfo.config.enabled) return 0;

        const debugCfg = { config: {...config, source: null}, source };
        cfg.debug(commentJson.stringify(debugCfg, undefined, 2));
        const startTime = Date.now();
        const wordOffsets = await cspell.validateText(text, info.configInfo.config);
        const issues = cspell.Text.calculateTextDocumentOffsets(filename, text, wordOffsets);
        const elapsed = (Date.now() - startTime) / 1000.0;
        const dictionaries = config.dictionaries || [];
        cfg.info(
            `Checking: ${filename}, File type: ${config.languageId}, Language: ${config.language} ... Issues: ${issues.length} ${elapsed}S`,
            MessageTypes.Info
        );
        cfg.info(`Dictionaries Used: ${dictionaries.join(', ')}`, MessageTypes.Info);
        issues
            .filter(cfg.uniqueFilter)
            .forEach((issue) => cfg.logIssue(issue));
        return issues.length;
    }