Javascript (ES6) (削除) 50 (削除ここまで) 44 Bytes (non-competing)

a=>a+=[,"st","nd","rd"][a.match`1?.$`]||"th"

Notes

• takes imput as a string
• Removed 6 bytes, thanks @user81655

Javascript (ES6) (削除) 50 (削除ここまで) 44 Bytes

a=>a+=[,"st","nd","rd"][a.match`1?.$`]||"th"

Notes

• takes imput as a string
• Removed 6 bytes, thanks @user81655

Javascript (ES6) (削除) 50 (削除ここまで) 44 Bytes (non-competing)

a=>a+=[,"st","nd","rd"][a.match`1?.$`]||"th"

###Notes###

• takes imput as a string
• Removed 6 bytes, thanks @user81655

Javascript (ES6) (削除) 50 (削除ここまで) 44 Bytes (non-competing)

a=>a+=[,"st","nd","rd"][a.match`1?.$`]||"th"

Notes

• takes imput as a string
• Removed 6 bytes, thanks @user81655

Javascript (ES6) (削除) 50 (削除ここまで) 44 Bytes

a=>a+=[,"st","nd","rd"][a.match`1?.$`]||"th"

###Notes###

• takes imput as a string
• Removed 6 bytes, thanks @user81655

Javascript (ES6) (削除) 50 (削除ここまで) 44 Bytes (non-competing)

a=>a+=[,"st","nd","rd"][a.match`1?.$`]||"th"

###Notes###

• takes imput as a string
• Removed 6 bytes, thanks @user81655