yaak-mountain-loop/plugins/template-function-regex/src/index.ts

import type { CallTemplateFunctionArgs, Context, PluginDefinition } from "@yaakapp/api";
import type { TemplateFunctionArg } from "@yaakapp-internal/plugins";

const inputArg: TemplateFunctionArg = {
  type: "text",
  name: "input",
  label: "Input Text",
  multiLine: true,
};

const regexArg: TemplateFunctionArg = {
  type: "text",
  name: "regex",
  label: "Regular Expression",
  placeholder: "\\w+",
  defaultValue: ".*",
  description:
    "A JavaScript regular expression. Use a capture group to reference parts of the match in the replacement.",
};

export const plugin: PluginDefinition = {
  templateFunctions: [
    {
      name: "regex.match",
      description: "Extract text using a regular expression",
      args: [inputArg, regexArg],
      previewArgs: [regexArg.name],
      async onRender(_ctx: Context, args: CallTemplateFunctionArgs): Promise<string | null> {
        const input = String(args.values.input ?? "");
        const regex = new RegExp(String(args.values.regex ?? ""));

        const match = input.match(regex);
        return match?.groups
          ? (Object.values(match.groups)[0] ?? "")
          : (match?.[1] ?? match?.[0] ?? "");
      },
    },
    {
      name: "regex.replace",
      description: "Replace text using a regular expression",
      previewArgs: [regexArg.name],
      args: [
        inputArg,
        regexArg,
        {
          type: "text",
          name: "replacement",
          label: "Replacement Text",
          placeholder: "hello $1",
          description:
            "The replacement text. Use $1, $2, ... to reference capture groups or $& to reference the entire match.",
        },
        {
          type: "text",
          name: "flags",
          label: "Flags",
          placeholder: "g",
          defaultValue: "g",
          optional: true,
          description:
            "Regular expression flags (g for global, i for case-insensitive, m for multiline, etc.)",
        },
      ],
      async onRender(_ctx: Context, args: CallTemplateFunctionArgs): Promise<string | null> {
        const input = String(args.values.input ?? "");
        const replacement = String(args.values.replacement ?? "");
        const flags = String(args.values.flags || "");
        const regex = String(args.values.regex);

        if (!regex) return "";

        return input.replace(new RegExp(String(args.values.regex), flags), replacement);
      },
    },
  ],
};