如何在const方法中返回

Question

Hi I am new to react so sorry for the basic question.

I am trying to define a method in a const

const Age = t.refinement(t.Number, (n) => return n >= 18);

However, the linter doesn't like that i have a return keyword in the method. Here is the class

import React, { Component } from 'react'
import { postFeedback } from 'Services/Config'
import { render } from 'react-dom';
import t from 'tcomb-form';


const FormSchema = t.struct({
    name: t.String,         // a required string
    age: t.Number, // an optional number
    rememberMe: t.Boolean   // a boolean
})

const Age = t.refinement(t.Number, (n) => return n >= 18);

export class Form extends Component {

onSubmit = (evt) => {
    evt.preventDefault()
    const value = this.refs.form.getValue()
    console.log(value)
    console.log("validation ->   " + this.refs.form.validate())
    if (value) {
        console.log(value)
    }
}

render() {
    return (
        <form onSubmit={this.onSubmit}>
            <t.form.Form ref="form" type={FormSchema} />
            <div className="form-group">
                <button type="submit" className="btn btn-primary">Save</button>
            </div>
        </form>
    )
}

}


export default Form

Answer 1

This is an anonymous ES2015 Arrow function , this is not related to the const key word.
Arrow functions returns implicitly or explicitly, depends if you are using a function body block {} .

Either do this (explicit return):

const Age = t.refinement(t.Number, (n) => {return n >= 18});

Or do this (implicit return):

const Age = t.refinement(t.Number, (n) => n >= 18);