Function schemeOf

packages/agent-core/src/utils/proxy.ts:36–38

Lowercase URL scheme (without the trailing colon), or undefined if absent.

(value: string)

/** Lowercase URL scheme (without the trailing colon), or undefined if absent. */
function schemeOf(value: string): string | undefined {
  return /^([a-z][a-z0-9+.-]*):/i.exec(value)?.[1]?.toLowerCase();
}

/** First non-blank value among `keys` (both casings are passed in by callers). */
function firstNonBlank(env: Env, keys: readonly string[]): string | undefined {