一丢一丢的学webpack-EntryOptionPlugin

webpack在安装插件的时候，会安装EntryOptionPlugin

    new EntryOptionPlugin().apply(compiler);
    compiler.hooks.entryOption.call(options.context, options.entry);

简单的说，就是判断entry是字符串还是数组， 是字符串，说明是单入口，调用SingleEntryPlugin 是数组，说明是多入口，调用MultiEntryPlugin 是函数，说明是动态入口，调用DynamicEntryPlugin

代码也很简单

/**
 * @param {string} context context path
 * @param {EntryItem} item entry array or single path
 * @param {string} name entry key name
 * @returns {SingleEntryPlugin | MultiEntryPlugin} returns either a single or multi entry plugin
 */
const itemToPlugin = (context, item, name) => {
	if (Array.isArray(item)) {
		return new MultiEntryPlugin(context, item, name);
	}
	return new SingleEntryPlugin(context, item, name);
};

module.exports = class EntryOptionPlugin {
	/**
	 * @param {Compiler} compiler the compiler instance one is tapping into
	 * @returns {void}
	 */
	apply(compiler) {
		compiler.hooks.entryOption.tap("EntryOptionPlugin", (context, entry) => {
			if (typeof entry === "string" || Array.isArray(entry)) {
				itemToPlugin(context, entry, "main").apply(compiler);
			} else if (typeof entry === "object") {
				for (const name of Object.keys(entry)) {
					itemToPlugin(context, entry[name], name).apply(compiler);
				}
			} else if (typeof entry === "function") {
				new DynamicEntryPlugin(context, entry).apply(compiler);
			}
			return true;
		});
	}
};

TODO

1. SingleEntryPlugin
2. MultiEntryPlugin
3. DynamicEntryPlugin