api.js

/*
 * api.js
 *
 * Copyright (c) 2021 Andrea Cardaci <[email protected]>
 *
 * Deno port Copyright (C) 2022 Posit Software, PBC
 */

function arrayToObject(parameters) {
  const keyValue = {};
  parameters.forEach((parameter) => {
    const name = parameter.name;
    delete parameter.name;
    keyValue[name] = parameter;
  });
  return keyValue;
}

function decorate(to, category, object) {
  to.category = category;
  Object.keys(object).forEach((field) => {
    // skip the 'name' field as it is part of the function prototype
    if (field === "name") {
      return;
    }
    // commands and events have parameters whereas types have properties
    if (
      (category === "type" && field === "properties") ||
      field === "parameters"
    ) {
      to[field] = arrayToObject(object[field]);
    } else {
      to[field] = object[field];
    }
  });
}

function addCommand(chrome, domainName, command) {
  const commandName = `${domainName}.${command.name}`;
  const handler = (params, sessionId, callback) => {
    return chrome.send(commandName, params, sessionId, callback);
  };
  decorate(handler, "command", command);
  chrome[commandName] = chrome[domainName][command.name] = handler;
}

function addEvent(chrome, domainName, event) {
  const eventName = `${domainName}.${event.name}`;
  const handler = (sessionId, handler) => {
    if (typeof sessionId === "function") {
      handler = sessionId;
      sessionId = undefined;
    }
    const rawEventName = sessionId ? `${eventName}.${sessionId}` : eventName;
    if (typeof handler === "function") {
      chrome.on(rawEventName, handler);
      return () => chrome.removeListener(rawEventName, handler);
    } else {
      return new Promise((fulfill, _reject) => {
        chrome.once(rawEventName, fulfill);
      });
    }
  };
  decorate(handler, "event", event);
  chrome[eventName] = chrome[domainName][event.name] = handler;
}

function addType(chrome, domainName, type) {
  const typeName = `${domainName}.${type.id}`;
  const help = {};
  decorate(help, "type", type);
  chrome[typeName] = chrome[domainName][type.id] = help;
}

export function prepare(object, protocol) {
  // assign the protocol and generate the shorthands
  object.protocol = protocol;
  protocol.domains.forEach((domain) => {
    const domainName = domain.domain;
    object[domainName] = {};
    // add commands
    (domain.commands || []).forEach((command) => {
      addCommand(object, domainName, command);
    });
    // add events
    (domain.events || []).forEach((event) => {
      addEvent(object, domainName, event);
    });
    // add types
    (domain.types || []).forEach((type) => {
      addType(object, domainName, type);
    });
    // add utility listener for each domain
    object[domainName].on = (eventName, handler) => {
      return object[domainName][eventName](handler);
    };
  });
}