javascript array contains
var colors = ["red", "blue", "green"];
var hasRed = colors.includes("red"); //true
var hasYellow = colors.includes("yellow"); //false
javascript array contains
var colors = ["red", "blue", "green"];
var hasRed = colors.includes("red"); //true
var hasYellow = colors.includes("yellow"); //false
js test if array
if(Array.isArray(myVarToTest)) {
// myVatToTest is an array
} else {
// myVarToTest is not an array
}
javascript test if it is an array
// If you want to test if a variable (object) is an instance of
// an array. You can use the Array.isArray(varName) method
// this method takes one argument, the variable or object you want to test
// and returns true, if the argument is an array
// or false, if the argument is not an array
if (Array.isArray(object)) {
// is true
} else {
// is false
}
Array.isArray([1, 2, 3, 4]); // Returns true
Array.isArray(4); // returns false
// this could be used for flattening an array of arrays
how to check if something is array javascript
function isArray(value) {
return Object.prototype.toString.call(value) === "[object Array]";
}
javascript check if in array
var extensions = ["image/jpeg","image/png","image/gif"];
if(extensions.indexOf("myfiletype") === -1){
alert("Image must be .png, .jpg or .gif");
}
javascript check if array is in array
var array = [1, 3],
prizes = [[1, 3], [1, 4]],
includes = prizes.some(a => array.every((v, i) => v === a[i]));
console.log(includes);
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