Bookshelf JS：“this.hasOne”不是一个函数

Question

Attempting to work through the simplest examples of bookshelf, but can't get past a one-to-many relationship using "withRelated" in a fetch statement. Here is my code (with some things removed for privacy) representing a one-to-many from B to A.

"use strict";
var knex = require('knex') ({
    client: 'mysql',
    connection: {
        host: '127.0.0.1',
        user: '*******',
        password: '*******',
        database: '*******',
        charset: 'utf8'
    }
});

var bookshelf = require('bookshelf')(knex);

var A, B

A = bookshelf.Model.extend({
    tableName: 'A',
    propB: () => { 
         return this.hasOne(B, 'A_id') 
    }

B = bookshelf.Model.extend({
    tableName: 'B',
    propA: () => { return this.belongsTo(A, 'A_id') }
})

A.forge().fetch({withRelated: ['propB']}).then(function(x){console.log(x)})

However, running this I get "Unhandled rejection TypeError: this.hasOne is not a function", referring to the this.hasOne in A. If I remove the "withRelated" clause, it runs just as expected and returns the correct entry in the database.

Why am I receiving this error? More info: Nodejs: v4.4.1 Bookshelf: v0.9.4

Answer 1

You are using arrow functions which inherit this from its parent context. You need to use function() {} syntax, so that bookshelf can bind this correctly.

Answer 2

Shorthand function notation is shorter and binds to the this-context of the class.

var A = bookshelf.Model.extend({
    tableName: 'A',
    propB() { 
        return this.hasOne(B, 'A_id') 
    }
})