我有这样的数据：
scores: {
uid1: {
score: 15,
displayName: "Uciska"
},
uid2: {
score: 3,
displayName: "Bob"
},
uid3: {
etc...
}
}
我想按分数对它们进行排名，只保留前 100 名。
我是按照文档做到的。但它不起作用。即使分数发生变化，它也始终返回相同的顺序。
const query = firebase.database().ref('scores')
.orderByChild('score')
.limitToLast(100)
query.on('child_added', snapshot => {
const score = snapshot.val().score
console.log(score)
})
我也在优化规则中添加了这一点，但我不确定它是否正确：
"scores": {
".indexOn": ["score"]
}
正确的方法是什么？
我正在尝试将Snipcart整合到Gatsby(第2版)中.
我html.js像这样编辑文件:
import React from "react"
import PropTypes from "prop-types"
export default class HTML extends React.Component {
render() {
return (
<html {...this.props.htmlAttributes}>
<head>
<meta charSet="utf-8" />
<meta httpEquiv="x-ua-compatible" content="ie=edge" />
<meta
name="viewport"
content="width=device-width, initial-scale=1, shrink-to-fit=no"
/>
{this.props.headComponents}
{/* Snipcart */}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<script src="https://cdn.snipcart.com/scripts/2.0/snipcart.js" id="snipcart" data-api-key="UF45pIjZjAtZWJkYS00MGEwLWIxZWEtNjljZThjNTRiNjA4NjM2NDg1MzAzMzQyNfDrr48"></script>
<link href="https://cdn.snipcart.com/themes/2.0/base/snipcart.min.css" type="text/css" rel="stylesheet" />
</head>
<body {...this.props.bodyAttributes}>
{this.props.preBodyComponents}
<div
key={`body`}
id="___gatsby"
dangerouslySetInnerHTML={{ __html: this.props.body }}
/>
{this.props.postBodyComponents}
</body>
</html>
)
}
}
HTML.propTypes = {
htmlAttributes: PropTypes.object,
headComponents: PropTypes.array,
bodyAttributes: …我用Gatsby和Netlify编写了一个应用程序。
我正在通过我的环境变量使用Snipcart公共 API 密钥html.js（在 dev 中有测试密钥，在 prod 中有实时密钥）。
import React from 'react'
import PropTypes from 'prop-types'
export default class HTML extends React.Component {
render() {
return (
<html lang='en' {...this.props.htmlAttributes}>
<head>
<meta charSet='utf-8' />
<meta httpEquiv='x-ua-compatible' content='ie=edge' />
<meta
name='viewport'
content='width=device-width, initial-scale=1, shrink-to-fit=no'
/>
{this.props.headComponents}
{/* Snipcart */}
<script
defer
src='https://ajax.googleapis.com/ajax/libs/jquery/2.2.2/jquery.min.js'
/>
<script
defer
src='https://cdn.snipcart.com/scripts/2.0/snipcart.js'
id='snipcart'
data-api-key={process.env.SNIPCART_API_KEY}
/>
<link
href='https://cdn.snipcart.com/themes/2.0/base/snipcart.min.css'
type='text/css'
rel='stylesheet'
/>
</head>
<body {...this.props.bodyAttributes}>
{this.props.preBodyComponents}
<div
key={'body'} …