feat(prompt): add auto suggestion support

prompt/_generic_input.ts

@@ -4,34 +4,41 @@ import {
   GenericPromptOptions,
   GenericPromptSettings,
 } from "./_generic_prompt.ts";
-import { stripColor, underline } from "./deps.ts";
+import { dim, stripColor, underline } from "./deps.ts";
 
 /** Input keys options. */
 export interface GenericInputKeys {
   moveCursorLeft?: string[];
   moveCursorRight?: string[];
   deleteCharLeft?: string[];
   deleteCharRight?: string[];
+  complete?: string[];
+  selectNextHistory?: string[];
+  selectPreviousHistory?: string[];
   submit?: string[];
 }
 
 /** Generic input prompt options. */
 export interface GenericInputPromptOptions<T>
   extends GenericPromptOptions<T, string> {
   keys?: GenericInputKeys;
+  suggestions?: Array<string | number>;
 }
 
 /** Generic input prompt settings. */
 export interface GenericInputPromptSettings<T>
   extends GenericPromptSettings<T, string> {
   keys?: GenericInputKeys;
+  suggestions?: Array<string | number>;
 }
 
 /** Generic input prompt representation. */
 export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
   extends GenericPrompt<T, string, S> {
   protected inputValue = "";
   protected inputIndex = 0;
+  protected suggestionsIndex = 0;
+  protected suggestions: Array<string | number> = [];
 
   /**
    * Inject prompt value. Can be used for unit tests or pre selections.
@@ -53,10 +60,17 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
         moveCursorRight: ["right"],
         deleteCharLeft: ["backspace"],
         deleteCharRight: ["delete"],
+        complete: ["tab"],
+        selectNextHistory: ["up"],
+        selectPreviousHistory: ["down"],
         submit: ["enter", "return"],
         ...(settings.keys ?? {}),
       },
+      suggestions: settings.suggestions?.slice(),
     });
+    this.settings.suggestions?.unshift(
+      this.settings.default ? this.format(this.settings.default) : "",
+    );
   }
 
   protected message(): string {
@@ -66,7 +80,38 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
   }
 
   protected input(): string {
-    return underline(this.inputValue);
+    return underline(this.inputValue) + dim(this.getSuggestion());
+  }
+
+  protected render(): Promise<void> {
+    this.match();
+    return super.render();
+  }
+
+  protected getSuggestion(needle: string = this.inputValue): string {
+    return this.suggestions[this.suggestionsIndex]?.toString()
+      .substr(
+        needle.length,
+      ) ?? "";
+  }
+
+  protected match(needle: string = this.inputValue): void {
+    if (!this.settings.suggestions?.length) {
+      return;
+    }
+    this.suggestions = this.settings.suggestions
+      .filter((value: string | number) =>
+        value.toString().toLowerCase().startsWith(needle.toLowerCase())
+      );
+    this.suggestionsIndex = Math.min(
+      this.suggestions.length - 1,
+      Math.max(0, this.suggestionsIndex),
+    );
+  }
+
+  /** Get user input. */
+  protected getValue(): string {
+    return this.inputValue;
   }
 
   /**
@@ -85,18 +130,16 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
         }
         break;
 
-      // case "up": // scroll history?
-      //   break;
-      //
-      // case "down": // scroll history?
-      //   break;
-
       case this.isKey(this.settings.keys, "moveCursorLeft", event):
         this.moveCursorLeft();
         break;
 
       case this.isKey(this.settings.keys, "moveCursorRight", event):
-        this.moveCursorRight();
+        if (this.inputIndex < this.inputValue.length) {
+          this.moveCursorRight();
+        } else {
+          this.complete();
+        }
         break;
 
       case this.isKey(this.settings.keys, "deleteCharRight", event):
@@ -107,6 +150,18 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
         this.deleteChar();
         break;
 
+      case this.isKey(this.settings.keys, "selectNextHistory", event):
+        this.selectNextSuggestion();
+        break;
+
+      case this.isKey(this.settings.keys, "selectPreviousHistory", event):
+        this.selectPreviousSuggestion();
+        break;
+
+      case this.isKey(this.settings.keys, "complete", event):
+        this.complete();
+        break;
+
       case this.isKey(this.settings.keys, "submit", event):
         await this.submit();
         break;
@@ -118,10 +173,7 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
     }
   }
 
-  /**
-   * Add character to current input.
-   * @param char Char to add.
-   */
+  /** Add character to current input. */
   protected addChar(char: string): void {
     this.inputValue = this.inputValue.slice(0, this.inputIndex) + char +
       this.inputValue.slice(this.inputIndex);
@@ -146,9 +198,8 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
   protected deleteChar(): void {
     if (this.inputIndex > 0) {
       this.inputIndex--;
-      this.tty.cursorBackward(1);
-      this.inputValue = this.inputValue.slice(0, this.inputIndex) +
-        this.inputValue.slice(this.inputIndex + 1);
+      this.tty.cursorBackward();
+      this.deleteCharRight();
     }
   }
 
@@ -160,8 +211,29 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
     }
   }
 
-  /** Get input input. */
-  protected getValue(): string {
-    return this.inputValue;
+  protected complete(): void {
+    if (this.suggestions.length) {
+      this.inputValue += this.getSuggestion();
+      this.inputIndex = this.inputValue.length;
+      this.suggestionsIndex = 0;
+    }
+  }
+
+  /** Select previous suggestion. */
+  protected selectPreviousSuggestion(): void {
+    if (this.settings.suggestions?.length) {
+      if (this.suggestionsIndex > 0) {
+        this.suggestionsIndex--;
+      }
+    }
+  }
+
+  /** Select next suggestion. */
+  protected selectNextSuggestion(): void {
+    if (this.settings.suggestions?.length) {
+      if (this.suggestionsIndex < this.suggestions.length - 1) {
+        this.suggestionsIndex++;
+      }
+    }
   }
 }

prompt/_generic_prompt.ts

@@ -148,7 +148,8 @@ export abstract class GenericPrompt<
   protected async read(): Promise<boolean> {
     if (typeof GenericPrompt.injectedValue !== "undefined") {
       const value: V = GenericPrompt.injectedValue as V;
-      return this.#validateValue(value);
+      await this.#validateValue(value);
+      return true;
     }
 
     const events: KeyEvent[] = await this.#readKey();
@@ -164,7 +165,7 @@ export abstract class GenericPrompt<
     return typeof this.#value !== "undefined";
   }
 
-  protected submit(): Promise<boolean> {
+  protected submit(): Promise<void> {
     return this.#validateValue(this.getValue());
   }
 
@@ -269,16 +270,19 @@ export abstract class GenericPrompt<
   };
 
   /**
-   * Map input value to output value. If a default value is set, the default
-   * will be used as value without any validation. If a custom validation
-   * handler ist set, the custom handler will be executed, otherwise the default
-   * validation handler from the prompt will be executed.
-   * @param value
+   * Validate input value. Set error message if validation fails and transform
+   * output value on success.
+   * If a default value is set, the default will be used as value without any
+   * validation.
+   * If a custom validation handler ist set, the custom handler will
+   * be executed, otherwise a prompt specific default validation handler will be
+   * executed.
+   * @param value The value to validate.
    */
-  #validateValue = async (value: V): Promise<boolean> => {
+  #validateValue = async (value: V): Promise<void> => {
     if (!value && typeof this.settings.default !== "undefined") {
       this.#value = this.settings.default;
-      return true;
+      return;
     }
 
     this.#value = undefined;
@@ -296,8 +300,6 @@ export abstract class GenericPrompt<
     } else {
       this.#value = this.#transformValue(value);
     }
-
-    return typeof this.#value !== "undefined";
   };
 
   /**
@@ -306,8 +308,7 @@ export abstract class GenericPrompt<
    * @param name  Key name.
    * @param event Key event.
    */
-  // deno-lint-ignore no-explicit-any
-  protected isKey<K extends any, N extends keyof K>(
+  protected isKey<K extends unknown, N extends keyof K>(
     keys: K | undefined,
     name: N,
     event: KeyEvent,

prompt/confirm.ts

@@ -10,7 +10,8 @@ import {
 export type ConfirmKeys = GenericInputKeys;
 
 /** Confirm prompt options. */
-export interface ConfirmOptions extends GenericInputPromptOptions<boolean> {
+export interface ConfirmOptions
+  extends Omit<GenericInputPromptOptions<boolean>, "suggestions"> {
   active?: string;
   inactive?: string;
   keys?: ConfirmKeys;
@@ -38,6 +39,10 @@ export class Confirm extends GenericInput<boolean, ConfirmSettings> {
       inactive: "No",
       pointer: blue(Figures.POINTER_SMALL),
       ...options,
+      suggestions: [
+        options.active ?? "Yes",
+        options.inactive ?? "No",
+      ],
     }).prompt();
   }
 

prompt/list.ts

@@ -1,4 +1,4 @@
-import { blue, stripColor, underline } from "./deps.ts";
+import { blue, dim, stripColor, underline } from "./deps.ts";
 import { Figures } from "./figures.ts";
 import {
   GenericInput,
@@ -62,7 +62,8 @@ export class List extends GenericInput<string[], ListSettings> {
 
     return oldInputParts
       .map((val: string) => underline(val))
-      .join(separator);
+      .join(separator) +
+      dim(this.getSuggestion());
   }
 
   /** Create list regex.*/
@@ -72,6 +73,18 @@ export class List extends GenericInput<string[], ListSettings> {
     );
   }
 
+  protected getSuggestion(
+    needle: string = this.inputValue.split(this.regexp()).pop() as string,
+  ): string {
+    return super.getSuggestion(needle);
+  }
+
+  protected match(
+    needle: string = this.inputValue.split(this.regexp()).pop() as string,
+  ): void {
+    super.match(needle);
+  }
+
   /** Add char. */
   protected addChar(char: string): void {
     switch (char) {

prompt/number.ts

@@ -75,6 +75,16 @@ export class Number extends GenericInput<number, NumberSettings> {
         }
         break;
 
+      case this.settings.suggestions &&
+        this.isKey(this.settings.keys, "selectNextHistory", event):
+        this.selectNextSuggestion();
+        break;
+
+      case this.settings.suggestions &&
+        this.isKey(this.settings.keys, "selectPreviousHistory", event):
+        this.selectPreviousSuggestion();
+        break;
+
       case this.isKey(this.settings.keys, "increaseValue", event):
         this.increaseValue();
         break;
@@ -88,7 +98,11 @@ export class Number extends GenericInput<number, NumberSettings> {
         break;
 
       case this.isKey(this.settings.keys, "moveCursorRight", event):
-        this.moveCursorRight();
+        if (this.inputIndex < this.input.length) {
+          this.moveCursorRight();
+        } else {
+          this.complete();
+        }
         break;
 
       case this.isKey(this.settings.keys, "deleteCharRight", event):
@@ -99,6 +113,10 @@ export class Number extends GenericInput<number, NumberSettings> {
         this.deleteChar();
         break;
 
+      case this.isKey(this.settings.keys, "complete", event):
+        this.complete();
+        break;
+
       case this.isKey(this.settings.keys, "submit", event):
         await this.submit();
         break;

prompt/secret.ts

@@ -19,7 +19,8 @@ import {
 export type SecretKeys = GenericInputKeys;
 
 /** Secret prompt options. */
-export interface SecretOptions extends GenericInputPromptOptions<string> {
+export interface SecretOptions
+  extends Omit<GenericInputPromptOptions<string>, "suggestions"> {
   label?: string;
   hidden?: boolean;
   minLength?: number;
@@ -28,7 +29,8 @@ export interface SecretOptions extends GenericInputPromptOptions<string> {
 }
 
 /** Secret prompt settings. */
-interface SecretSettings extends GenericInputPromptSettings<string> {
+interface SecretSettings
+  extends Omit<GenericInputPromptSettings<string>, "suggestions"> {
   label: string;
   hidden: boolean;
   minLength: number;