How do I check whether an array contains a string in TypeScript?
The same as in JavaScript, using Array.prototype.indexOf():
console.log(channelArray.indexOf('three') > -1);Or using ECMAScript 2016 Array.prototype.includes():
console.log(channelArray.includes('three'));Note that you could also use methods like showed by @Nitzan to find a string. However you wouldn't usually do that for a string array, but rather for an array of objects. There those methods were more sensible. For example
const arr = [{foo: 'bar'}, {foo: 'bar'}, {foo: 'baz'}];console.log(arr.find(e => e.foo === 'bar')); // {foo: 'bar'} (first match)console.log(arr.some(e => e.foo === 'bar')); // trueconsole.log(arr.filter(e => e.foo === 'bar')); // [{foo: 'bar'}, {foo: 'bar'}]Reference
You can use the some method:
console.log(channelArray.some(x => x === "three")); // trueYou can use the find method:
console.log(channelArray.find(x => x === "three")); // threeOr you can use the indexOf method:
console.log(channelArray.indexOf("three")); // 2
Also note that "in" keyword does not work on arrays. It works on objects only.
propName in myObjectArray inclusion test is
myArray.includes('three');