function isOnlyEnglishLetters(s: string) {
const pattern: RegExp = /^[a-zA-Z]+$/;
return pattern.test(s);
}
const s1: string = "TypeScript";
console.log(isOnlyEnglishLetters(s1));
const s2: string = "TypeScriptタイプスクリプト";
console.log(isOnlyEnglishLetters(s2));
/*
run:
true
false
*/