TextInput输入空格

Question

我正在开发React本机应用程序。使用TextInput作为名字或姓氏。当在空白textInput框上输入文本时输入空格按钮时，TextInput为空。然后，我将检查是否为空。他在textInput上显示了一些价值。但是我没有在textinput上输入任何值或仅输入空格。我认为他将空间视为角色。因此，请帮助我检查这种情况。

 <TextInput 
                                        placeholder="Joe" 
                                        autoFocus={false} 
                                        returnKeyType={"next"} 
                                        blurOnSubmit={false}
                                        onChangeText={firstName => this.setState({ firstName })}
                                        onSubmitEditing={(event) => {this.passTextInput1.focus()}}
                                        style={styles.textBox1} />
                                    <TextInput
                                        placeholder="Bloggs" 
                                        inputRef={(input) => {this.passTextInput1 = input}}
                                        returnKeyType={"next"}
                                        onChangeText={lastName => this.setState({ lastName })}
                                        onSubmitEditing={(event) => this.onValidations()}
                                        style={styles.textBox2} />


    Condition:
    if(this.state.firstName == '' && this.state.lastName == ''){
                  Alert.alert('Please fill the required fields')
              } else if(this.state.firstName == '') {
                  Alert.alert('Please fill the First Name')
              } else if(this.state.lastName == '') {
                  Alert.alert('Please fill the Last Name')
              } else {

                    this.props.navigation.navigate('AccountStep2', {
                        Firstname: this.state.firstName,
                        Lastname: this.state.lastName,
                      })
              }




    Textinput Check empty or not. when textInput is empty. when click on space button. than check condition he show some value on textinput

Answer 1

修剪功能可以删除空间。

https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/String/trim