{"id":1539,"date":"2020-09-24T16:05:00","date_gmt":"2020-09-24T08:05:00","guid":{"rendered":"https:\/\/www.yusian.com\/blog\/?p=1539"},"modified":"2020-10-31T16:07:21","modified_gmt":"2020-10-31T08:07:21","slug":"promise%e7%9a%84%e7%ae%80%e5%8d%95%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/www.yusian.com\/blog\/javascript\/2020\/09\/24\/1605001539.html","title":{"rendered":"Promise\u7684\u7b80\u5355\u5b9e\u73b0"},"content":{"rendered":"<p>1\u3001Promise\u5728javascript\u4e2d\u7684\u91cd\u8981\u6027\u4e0d\u8a00\u800c\u55bb\uff0c\u4f46\u5f88\u591a\u540c\u5b66\u5e76\u4e0d\u6e05\u695a\u5185\u90e8\u7684\u5b9e\u73b0\u673a\u7406\uff0c\u6211\u5c31\u6211\u7684\u7406\u89e3\u4e0e\u5927\u5bb6\u5206\u4eab\u4e00\u4e0b\uff1b<\/p>\n<p>2\u3001\u6700\u7b80\u5355\u7684\u529e\u6cd5\u5c31\u662f\u6839\u636e\u5b98\u65b9\u7684Promise\u6548\u679c\u6765\u5b9e\u73b0\u76f8\u540c\u7684\u6548\u679c\uff0c\u6211\u4e4b\u524d\u4e5f\u770b\u8fc7\u7f51\u4e0a\u7684\u76f8\u5173\u5b9e\u73b0\uff0c\u5168\u7bc7\u770b\u5230\u5e95\u5c31\u61f5\u4e86\uff0c\u6211\u60f3\u80fd\u4e0d\u80fd\u51fa\u6d45\u5165\u6df1\u4e00\u6b65\u4e00\u6b65\u6765\uff1b<\/p>\n<p>3\u3001\u597d\u4e86\uff0c\u5148\u5b9e\u73b0\u4e00\u4e2a\u6700\u7b80\u5355\u7684\uff0c\u53ea\u5b9e\u73b0then\u65b9\u6cd5\uff0c\u80fd\u591f\u6839\u636eresolve\u4e0ereject\u53d6\u5230\u76f8\u5173\u7ed3\u679c\uff0c\u4ec5\u505a\u529f\u80fd\u5b9e\u73b0\uff0c\u540e\u7eed\u518d\u5b8c\u5584<\/p>\n<p><code>1\u3001promise.js<\/code><\/p>\n<pre><code class=\"language-javascript line-numbers\">\/**\n * Promise\u7b80\u5355\u5b9e\u73b0 v0.0.1\n *\n * Date:2020-09-24\n *\n * Author:yusian\n *\/\n(function (window) {\n    \/**\n     * Promise\u72b6\u6001\u503c\n     *\/\n    const PROMISE_STATE = {\n        PENDING: 'pending',\n        FILFULLED: 'filfulled',\n        REJECTED: 'rejected'\n    }\n    \/**\n     * \u6784\u9020\u51fd\u6570\uff0c\u751f\u6210\u4e00\u4e2aPromise\u5bf9\u8c61\uff0c\u53c2\u6570\u4e3a\u51fd\u6570\n     * \u4f20\u5165\u7684\u51fd\u6570\u5e26\u67092\u4e2a\u53c2\u6570\uff0c\u5206\u522b\u4e3aresolve\u4e0ereject\n     * resolve\u4e3a\u5e26\u6709value\u503c\u7684\u6210\u529f\u56de\u8c03\n     * reject\u4e3a\u5e26\u6709reason\u503c\u7684\u5931\u8d25\u56de\u8c03\n     * @param {Function} excutor \u6267\u884c\u5668\u51fd\u6570\n     *\/\n    function Promise(excutor) {\n        let self = this;\n        this.state = PROMISE_STATE.PENDING;\n        this.data = undefined;\n        this.onResolvedCallbacks = [];\n        this.onRejectedCallbacks = [];\n\n        \/**\n         * \u6210\u529f\u56de\u8c03\n         * @param {any} value \u6210\u529f\u56de\u8c03\u503c\n         *\/\n        function resolve(value) {\n            if (self.state !== PROMISE_STATE.PENDING) return;\n            self.state = PROMISE_STATE.FILFULLED;\n            self.data = value;\n            self.onResolvedCallbacks.forEach(function (callback) {\n                callback(value);\n            })\n        }\n\n        \/**\n         * \u5931\u8d25\u56de\u8c03\n         * @param {any} reason \u5931\u8d25\u56de\u8c03\u503c\u6216Error\n         *\/\n        function reject(reason) {\n            if (self.state !== PROMISE_STATE.PENDING) return;\n            self.state = PROMISE_STATE.REJECTED;\n            self.data = reason;\n            self.onRejectedCallbacks.forEach(function (callback) {\n                callback(reason);\n            })\n        }\n\n        \/**\n         * \u540c\u6b65\u6267\u884c\u5f02\u6b65\u4efb\u52a1\uff0c\u5982\u6709\u5f02\u5e38\u53ca\u65f6\u629b\u51fa\u5e76\u7ed3\u675f\u4efb\u52a1\uff0c\u8c03\u7528\u5931\u8d25\u56de\u8c03\n         *\/\n        try {\n            excutor(resolve, reject);\n        } catch (error) {\n            reject(error);\n        }\n    }\n    \/**\n     * Promise\u56de\u8c03\uff0c\u5f02\u6b65\u4efb\u52a1\u6267\u884c\u7ed3\u675f\u540e\u4f1a\u6267\u884c\u8be5\u56de\u8c03\n     * \u8be5\u65b9\u6cd5\u8c03\u7528\u53ef\u4ee5\u5728\u5f02\u6b65\u6267\u884c\u7ed3\u675f\u524d\u6216\u7ed3\u675f\u540e\uff0c\u4e0d\u5f71\u54cd\u56de\u8c03\n     * @param {Function} onResolve \u6210\u529f\u56de\u8c03\n     * @param {Function} onReject \u5931\u8d25\u56de\u8c03\n     *\/\n    Promise.prototype.then = function (onResolve, onReject) {\n        let self = this;\n        \/\/ \u5982\u679c\u662fpending\u72b6\u6001\uff0c\u5219\u6682\u65f6\u5c06\u56de\u8c03\u52a0\u5165\u5230\u961f\u5217\u4e2d\u7b49\u5f85\u6267\u884c\n        if (self.state === PROMISE_STATE.PENDING) {\n            self.onResolvedCallbacks.push(function () {\n                setTimeout(function () { onResolve(self.data); })\n            })\n            self.onRejectedCallbacks.push(function () {\n                setTimeout(function () { onReject(self.data); })\n            })\n        }\n        \/\/ \u5982\u679c\u662ffilfulled\u72b6\u6001\uff0c\u5219\u6267\u884c\u4f20\u5165\u7684onResolve\u51fd\u6570\n        else if (self.state === PROMISE_STATE.FILFULLED) {\n            setTimeout(function () { onResolve(self.data); });\n        }\n        \/\/ \u5982\u679c\u662frejected\u72b6\u6001\uff0c\u5219\u6267\u884c\u4f20\u5165\u7684onReject\u51fd\u6570\n        else if (self.state === PROMISE_STATE.REJECTED) {\n            setTimeout(function () { onReject(self.data); });\n        }\n    }\n    \/**\n     * \u5168\u5c40\u8bbf\u95ee\n     *\/\n    window.Promise = Promise;\n})(window)\n<\/code><\/pre>\n<p><code>2\u3001index.html<\/code><\/p>\n<pre data-language=HTML><code class=\"language-markup line-numbers\">&lt;!DOCTYPE html&gt;\n&lt;html lang=\"en\"&gt;\n\n&lt;head&gt;\n    &lt;meta charset=\"UTF-8\"&gt;\n    &lt;meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\"&gt;\n    &lt;title&gt;Promise\u7b80\u5355\u5b9e\u73b0&lt;\/title&gt;\n    &lt;script src=\"lib\/promise.js\"&gt;&lt;\/script&gt;\n&lt;\/head&gt;\n\n&lt;body&gt;\n    &lt;script&gt;\n        console.log(1);\n        let p = new Promise(function (resolve, reject) {\n            console.log(2);\n            resolve(2);\n        });\n        console.log(p);\n        p.then(function (value) {\n            console.log(4);\n            console.log('onResolve:', value);\n        }, function (reason) {\n            console.log(4);\n            console.log('onReject:', reason);\n        })\n        console.log(3);\n    &lt;\/script&gt;\n&lt;\/body&gt;\n\n&lt;\/html&gt;\n<\/code><\/pre>\n<p>\u63a7\u5236\u53f0\u8f93\u51fa\u7ed3\u679c\uff1a<\/p>\n<pre><code class=\"line-numbers\">1\n2\nPromise\u00a0{}\n3\n4\nonResolve: 2\n<\/code><\/pre>\n<p><strong>\u89e3\u91ca\u8bf4\u660e\uff1a<\/strong><br \/>\n* \u4e3a\u4ec0\u4e48\u9700\u8981Promise\uff1f\u4f20\u7edf\u7684\u7684\u5f02\u6b65\u4efb\u52a1\u9700\u8981\u5728\u6267\u884c\u524d\u4f20\u5165\u56de\u8c03\u51fd\u6570\u6765\u83b7\u53d6\u7ed3\u679c\uff0c\u8fd9\u5f88\u4e0d\u65b9\u4fbf\uff0c\u4e5f\u4e0d\u7075\u6d3b\uff0c\u6bd4\u5982\u80fd\u4e0d\u80fd\u5728\u6211\u6307\u5b9a\u7684\u65f6\u673a\u56de\u8c03\uff1f\u6211\u8981\u591a\u70b9\u89e6\u53d1\u600e\u4e48\u529e\uff1f<br \/>\n* Promise\u4e2d\u7684\u91cd\u70b9\u662f\u5c06\u5f02\u6b65\u4efb\u52a1\u4e2d\u7684<code>\u56de\u8c03\u65b9\u6cd5<\/code>\u4e0e<code>\u7ed3\u679c<\/code>\u5206\u522b\u5728promise\u5bf9\u8c61\u4e2d\u4fdd\u5b58\uff0c\u5728 <strong>\u9002\u5f53<\/strong> \u7684\u65f6\u673a\u8fdb\u884c\u56de\u8c03\uff0c\u8fd9\u8ba9\u4efb\u52a1\u7684\u6267\u884c\u4e0e\u7ed3\u679c\u7684\u5904\u7406\u8fdb\u884c\u4e86\u5206\u79bb\uff1b<br \/>\n* \u5f53\u524d\u53ea\u662f\u5b9e\u73b0\u4e86then\u65b9\u6cd5\uff0c\u53ef\u4ee5\u83b7\u53d6\u5f02\u6b65\u4efb\u52a1\u7684resolve\u6216reject\u56de\u8c03\uff0c\u4f46\u8fd8\u4e0d\u652f\u6301\u94fe\u5f0f\u8c03\u7528\uff0c\u4e5f\u6ca1\u6709\u5b9e\u73b0catch\u65b9\u6cd5\uff1b<br \/>\n* \u76f8\u5173\u8bf4\u660e\u5df2\u7ecf\u6ce8\u91ca\u4e2d\u6807\u660e\uff0c\u5bf9\u4e8e\u7406\u89e3Promise\u5e94\u8be5\u6709\u6240\u5e2e\u52a9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>1\u3001Promise\u5728javascript\u4e2d\u7684\u91cd\u8981\u6027\u4e0d\u8a00\u800c\u55bb\uff0c\u4f46\u5f88\u591a\u540c\u5b66\u5e76\u4e0d\u6e05\u695a\u5185\u90e8\u7684\u5b9e\u73b0\u673a\u7406\uff0c\u6211\u5c31\u6211\u7684\u7406\u89e3\u4e0e\u5927\u5bb6\u5206\u4eab\u4e00\u4e0b\uff1b 2\u3001\u6700\u7b80\u5355\u7684\u529e\u6cd5\u5c31\u662f\u6839\u636e\u5b98\u65b9\u7684Promise\u6548\u679c\u6765\u5b9e\u73b0\u76f8\u540c\u7684\u6548\u679c\uff0c\u6211\u4e4b\u524d\u4e5f\u770b\u8fc7\u7f51\u4e0a\u7684\u76f8\u5173\u5b9e\u73b0\uff0c\u5168\u7bc7\u770b\u5230\u5e95\u5c31\u61f5\u4e86\uff0c\u6211\u60f3\u80fd\u4e0d\u80fd\u51fa\u6d45\u5165\u6df1\u4e00\u6b65\u4e00\u6b65\u6765\uff1b 3\u3001\u597d\u4e86\uff0c\u5148\u5b9e\u73b0\u4e00\u4e2a\u6700\u7b80\u5355\u7684\uff0c\u53ea\u5b9e\u73b0then\u65b9\u6cd5\uff0c\u80fd\u591f\u6839\u636eresolve\u4e0ereject\u53d6\u5230\u76f8\u5173\u7ed3\u679c\uff0c\u4ec5\u505a\u529f\u80fd\u5b9e\u73b0\uff0c\u540e\u7eed\u518d\u5b8c\u5584 1\u3001promise.js \/** * Promise\u7b80\u5355\u5b9e\u73b0 v0.0.1 * * Date:2020-09-24 * * Author:yusian *\/ (function (window) { \/** * Promise\u72b6\u6001\u503c *\/ const PROMISE_STATE = { PENDING: &#8216;pending&#8217;, FILFULLED: &#8216;filfulled&#8217;, REJECTED: &#8216;rejected&#8217; } \/** * \u6784\u9020\u51fd\u6570\uff0c\u751f\u6210\u4e00\u4e2aPromise\u5bf9\u8c61\uff0c\u53c2\u6570\u4e3a\u51fd\u6570 * \u4f20\u5165\u7684\u51fd\u6570\u5e26\u67092\u4e2a\u53c2\u6570\uff0c\u5206\u522b\u4e3aresolve\u4e0ereject * resolve\u4e3a\u5e26\u6709value\u503c\u7684\u6210\u529f\u56de\u8c03 * reject\u4e3a\u5e26\u6709reason\u503c\u7684\u5931\u8d25\u56de\u8c03 * @param {Function} excutor \u6267\u884c\u5668\u51fd\u6570 *\/ function Promise(excutor) { let self = this; [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[28],"tags":[230,53,236,237],"class_list":["post-1539","post","type-post","status-publish","format-standard","hentry","category-javascript","tag-es6","tag-javascript","tag-promise","tag-237"],"_links":{"self":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/posts\/1539","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/comments?post=1539"}],"version-history":[{"count":0,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/posts\/1539\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/media?parent=1539"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/categories?post=1539"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.yusian.com\/blog\/wp-json\/wp\/v2\/tags?post=1539"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}