vscode-jsonrpc/lib/common/is.d.ts

A json rpc implementation over streams

export declare function boolean(value: any): value is boolean;
export declare function string(value: any): value is string;
export declare function number(value: any): value is number;
export declare function error(value: any): value is Error;
export declare function func(value: any): value is Function;
export declare function array<T>(value: any): value is T[];
export declare function stringArray(value: any): value is string[];