npm install -g dtsgenerator

$ dtsgen --help

  Usage: dtsgen [options] <file ... | file patterns using node-glob>

  Options:

    -h, --help        output usage information
    -V, --version     output the version number
    -o, --out [file]  output d.ts filename

dtsgen --out types.d.ts schema1.json schema2.json
dtsgen --out types.d.ts schema/**/*.schema.json