Sometimes you might want to call a function in Javascript but check if the function exists before calling it. This is very simple and is covered in this post. You can test if a function exists in Javascript by simply testing for the name of it in an if() conditional. One thing to be...
//code to check if a value exists in an array using javascript for loop var fruits_arr = ['Apple', 'Mango', 'Grapes', 'Orange', 'Fig', 'Cherry']; function checkValue(value, arr) { var status = 'Not exist'; for (var i = 0; i < arr.length; i++) { var name = arr[...
function checkePlugs(pluginname) { var f = "-" var plugins = navigator.plugins; if (plugins.length > 0) { for (i = 0; i < navigator.pluginslength; i++) { if (navigatorplugins[i].name.indexOf(plugin) >= 0) { f = navigator.plugins[i.descriptionsplit(pluginname)[1...
使用特定于应用程序的 Office JavaScript API生成外接程序时,请务必包含错误处理逻辑,以考虑运行时错误。 由于 API 的异步性质,这样做至关重要。 最佳做法 在我们的代码示例和Script Lab代码片段中,你会注意到,对、PowerPoint.run或Word.run的每个调用Excel.run都附带一个catch语句来捕获任何错误。 建议在使用特定...
7. `averageBy`:数组对象属性平均数 此代码段将获取数组对象属性的平均值 代码语言:javascript 复制 constaverageBy=(arr,fn)=>arr.map(typeoffn==='function'?fn:val=>val[fn]).reduce((acc,val)=>acc+val,0)/arr.length;averageBy([{n:4},{n:2},{n:8},{n:6}],o=>o.n);// 5averageBy...
functionf() {console.log(bar);// undefinedvarbar ='abc';console.log(bar);// abc} 我们可以看到变量“bar”已经存在于“f()”的第一行,但它还没有值;也就是说,声明已经被提升,但赋值没有。JavaScript 执行f()时,就好像它的代码是: functionf() {varbar;console.log(bar);// undefinedbar ='ab...
save(function(err) { if (err) done(err); else done(); }); }); }); }); Alternatively, just use the done() callback directly (which will handle an error argument, if it exists): describe('User', function() { describe('#save()', function() { it('should save without error'...
Provide a displayTickerAlert2 JS function. The following example returns a string for display by the caller:HTML Copy window.displayTickerAlert2 = (symbol, price) => { if (price < 20) { alert(`${symbol}: $${price}!`); return "User alerted in the browser."; } else { ret...
Provide a displayTickerAlert2 JS function. The following example returns a string for display by the caller:HTML Copy window.displayTickerAlert2 = (symbol, price) => { if (price < 20) { alert(`${symbol}: $${price}!`); return "User alerted in the browser."; } else { return "...
MemberDefinition.isComputed(): holds if the name of this member is computed at runtime. MemberDefinition.getName(): gets the name of this member if it can be determined statically. MemberDefinition.getInit(): gets the initializer of this field; for methods, the initializer is a function exp...