Method _removeUnneededFiles

server/src/analyzer/program.ts:446–494

()

    // that have been removed. This is needed to clear out the
    // errors for files that have been deleted or closed.
    private _removeUnneededFiles(): FileDiagnostics[] {
        let fileDiagnostics: FileDiagnostics[] = [];

        // If a file is no longer tracked or opened, it can
        // be removed from the program.
        for (let i = 0; i < this._sourceFileList.length; ) {
            let fileInfo = this._sourceFileList[i];
            if (!this._isFileNeeded(fileInfo)) {
                fileDiagnostics.push({
                    filePath: fileInfo.sourceFile.getFilePath(),
                    diagnostics: []
                });

                fileInfo.sourceFile.prepareForClose();
                delete this._sourceFileMap[fileInfo.sourceFile.getFilePath()];
                this._sourceFileList.splice(i, 1);

                // Unlink any imports and remove them from the list if
                // they are no longer referenced.
                fileInfo.imports.forEach(importedFile => {
                    let indexToRemove = importedFile.importedBy.findIndex(fi => fi === fileInfo);
                    assert(indexToRemove >= 0);
                    importedFile.importedBy.splice(indexToRemove, 1);

                    // See if we need to remove the imported file because it
                    // is no longer needed. If its index is >= i, it will be
                    // removed when we get to it.
                    if (!this._isFileNeeded(importedFile)) {
                        let indexToRemove = this._sourceFileList.findIndex(fi => fi === importedFile);
                        if (indexToRemove < i) {
                            fileDiagnostics.push({
                                filePath: importedFile.sourceFile.getFilePath(),
                                diagnostics: []
                            });

                            importedFile.sourceFile.prepareForClose();
                            delete this._sourceFileMap[importedFile.sourceFile.getFilePath()];
                            this._sourceFileList.splice(indexToRemove, 1);
                            i--;
                        }
                    }
                });
            } else {
                i++;
            }
        }

        return fileDiagnostics;
    }

    private _isFileNeeded(fileInfo: SourceFileInfo) {
        if (fileInfo.isTracked || fileInfo.isOpenByClient) {