[已注销] 实际上有个不成文的东西,就是你可以这样子写: function checkUrl(url) { return new Promise((resolve) => { fetch(url, { mode: 'no-cors', method: 'HEAD' }) .then(() => resolve(1), () => resolve()); }); }
[已注销] #5 James 这样子也可以 function checkUrl(u) { return new Promise(r=>{mode='no-cors',p=o=>r(o==mode),at=fetch,s=v=>{if(v==mode)return'HEAD';p(mode)},method=s(mode),o={mode,method,r,p},h=at(u,o);h.then(s,p,o,h);}); }
[已注销] #5 James 不过这样子写是没问题的,ES6允许的: function checkUrl(url) { return new Promise((resolve) => { fetch(url, { mode: 'no-cors', method: 'HEAD' }) .then(() => resolve(true), () => resolve(false)); }); }