The best way to check if an array is empty in JavaScript is by using the Array.isArray() method (ES5+) and array's length property together like so: // ES5+ if (!Array.isArray(array) || !array.length) { // ... } Similarly, using else, or the inverse would che...
typeof myObject === 'object' && myObject !== null The best way to check if the variable holds an array is to useArray.isArray(variable)built-in function. Becauseundefinedis falsy, you might be tempted to use it directly in conditionals. But such practice is error-prone. Better options...
We used thelogical OR (||)operator which returns the value to the right if the value to the left is falsy (e.g.undefined). The falsy values in JavaScript are:null,undefined,0,false,""(empty string),NaN(not a number). If any of the six aforementioned values is to the left of the...
In JavaScript values are inherentlytruthyorfalsywhen evaluated in a boolean context. The !! operator uses this behavior to convert any value totrueorfalse. Falsy Values ? false 0 "" (empty string) null undefined NaN All other values are consideredtruthy. Example Below is an example for the !
Object Function Array Date RegExp Null Undefined And there are some built inErrortypes as well. Things are a lot easier if we stick with the first diagram, though. Numbers Numbers in JavaScript are "double-precision 64-bit format IEEE 754 values", according to the spec. This has some inte...
In Lua, false is the only falsy value._.compact({0, 1, false, 2, '', 3}) => {0, 1, 2, '', 3}flatten_.flatten(array, [shallow])Flattens a nested array (the nesting can be to any depth). If you pass shallow, the array will only be flattened a single level....
Individual requests in a JSON-RPC batch will all receive the exact same context object in their handler - take care not to mutate it If a falsy context value is given to jayson.Server.prototype.call, an empty object will be created None of the current jayson server transports (http, https...
is.empty(value:array|object|string) Checks if the given value is empty. is.existy(value:any) Checks if the given value is existy. (not null or undefined) is.truthy(value:any) Checks if the given value is truthy. (existy and not false) is.falsy(value:any) Checks if the given valu...
JavaScript Number isFinite Method - Learn about the JavaScript Number isFinite method, how it works, and its importance in validating finite numbers in your code.
is.js是一个强大的通用js校验工具类。你可以使用js.js来检测任何东西,例如检测所给的值是否为参数,是否是数组,是否是超链接,...,甚至可以检测浏览器类型,正则表达式和数学表达式等等。 is.js根据检测的类型分为:类型检测、正则表达式检测、算数检测、环境检测、时间检测、Presence检测、对象检测、字符串检测数组检测...