If you recently upgraded Typescript, you’ll get an error like this:
typings/main/ambient/node/index.d.ts(426,11): error TS2430: Interface 'NodeBuffer' incorrectly extends interface 'Uint8Array'.
Types of property 'fill' are incompatible.
Type '(value: any, offset?: number, end?: number) => Buffer' is not assignable to type '(value: number, start?: number, end?: number) => this'.
Type 'Buffer' is not assignable to type 'this'.
The fix to this is to re-install the Node type bindings:
typings install 'dt!node' --save --global
rm -rf typings/
typings install