feat(cli): promptSecret()

cli/prompt_secret.ts

@@ -0,0 +1,81 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+const input = Deno.stdin;
+const output = Deno.stdout;
+const encoder = new TextEncoder();
+const decoder = new TextDecoder();
+const LF = "\n".charCodeAt(0); // ^J - Enter on Linux
+const CR = "\r".charCodeAt(0); // ^M - Enter on macOS and Windows (CRLF)
+const BS = "\b".charCodeAt(0); // ^H - Backspace on Linux and Windows
+const DEL = 0x7f; // ^? - Backspace on macOS
+const CLR = encoder.encode("\r\u001b[K"); // Clear the current line
+
+// The `cbreak` option is not supported on Windows
+const setRawOptions = Deno.build.os === "windows"
+  ? undefined
+  : { cbreak: true };
+
+export type PromptSecretOptions = {
+  /** A character to print instead of the user's input. */
+  mask?: string;
+  /** Clear the current line after the user's input. */
+  clear?: boolean;
+};
+
+/**
+ * Shows the given message and waits for the user's input. Returns the user's input as string.
+ * This is similar to `prompt()` but it print user's input as `*` to prevent password from being shown.
+ * Use an empty `mask` if you don't want to show any character.
+ */
+export function promptSecret(
+  message = "Secret ",
+  { mask = "*", clear }: PromptSecretOptions = {},
+): string | null {
+  if (!Deno.isatty(input.rid)) {
+    return null;
+  }
+
+  const callback = !mask ? undefined : (n: number) => {
+    output.writeSync(CLR);
+    output.writeSync(encoder.encode(`${message}${mask.repeat(n)}`));
+  };
+  output.writeSync(encoder.encode(message));
+
+  Deno.stdin.setRaw(true, setRawOptions);
+  try {
+    return readLineFromStdinSync(callback);
+  } finally {
+    if (clear) {
+      output.writeSync(CLR);
+    } else {
+      output.writeSync(encoder.encode("\n"));
+    }
+    Deno.stdin.setRaw(false);
+  }
+}
+
+// Slightly modified from Deno's runtime/js/41_prompt.js
+// This implementation immediately break on CR or LF and accept callback.
+// The original version waits LF when CR is received.
+// https://github.com/denoland/deno/blob/e4593873a9c791238685dfbb45e64b4485884174/runtime/js/41_prompt.js#L52-L77
+function readLineFromStdinSync(callback?: (n: number) => void): string {
+  const c = new Uint8Array(1);
+  const buf = [];
+
+  while (true) {
+    const n = input.readSync(c);
+    if (n === null || n === 0) {
+      break;
+    }
+    if (c[0] === CR || c[0] === LF) {
+      break;
+    }
+    if (c[0] === BS || c[0] === DEL) {
+      buf.pop();
+    } else {
+      buf.push(c[0]);
+    }
+    if (callback) callback(buf.length);
+  }
+  return decoder.decode(new Uint8Array(buf));
+}