in src/main.ts [443:452]
function runNpmInstall(arg: CommandArgument) {
let dirs = [];
// Is the command executed from the context menu?
if (arg && arg.fsPath) {
dirs.push(path.dirname(arg.fsPath));
} else {
dirs = getAllIncludedDirectories();
}
runNpmCommandInPackages(['install'], true, false, dirs);
}