在 Javascript 中将对象 Promise 转换为字符串
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/51250211/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Converting Object Promise to String in Javascript
提问by Saensation
I'm working with React, Next.Js, semantic-ui-react and Solidity. It is my goal to print out the users address (from MetaMask) and a ProjectTitle (set by User) as meta infomation for a semantic-ui-react card. To print out the address in the 'header' is working, but I'm not able to print out the ProjectTitle as 'meta'. The Title should be a String but I'm receiving a Object Promise.
我正在使用 React、Next.Js、semantic-ui-react 和 Solidity。我的目标是打印出用户地址（来自 MetaMask）和一个 ProjectTitle（由用户设置）作为语义 ui-react 卡片的元信息。打印出“标题”中的地址是有效的，但我无法将 ProjectTitle 打印为“元”。标题应该是一个字符串，但我收到了一个对象承诺。
static async getInitialProps() {
const projects = await factory.methods.getDeployedProjects().call();
return {
projects
};
}
async getProjectTitle(address) {
let title;
try {
title = await factory.methods.projectTitle(address).call();
} catch (err) {
console.log('err');
}
return title;
}
renderProjects() {
const items = this.props.projects.map(address => {
return {
header: address,
color: 'green',
description: (
<Link route={`/projects/${address}`}>
<a>View Project</a>
</Link>
),
**meta: this.getProjectTitle(address)**,
fluid: true,
style: { overflowWrap: 'break-word' }
};
}, );
return <Card.Group items={items} />
}
Part of the Solidity Contract:
Solidity 合约的一部分：
address[] public deployedProjects;
mapping(address => string) public projectTitle;
function createProject(string startup, string title, string deadline, string description, uint wage) public {
address newProject = new Project(startup, title, deadline, description, wage, msg.sender);
projectTitle[newProject] = title;
deployedProjects.push(newProject);
}
function getDeployedProjects() public view returns (address[]) {
return (
deployedProjects
);
}
The basic framework is from the Udemy Course "Ethereum and Solidity: The Complete Developer's Guide" by Stephen Grider.
基本框架来自 Stephen Grider 的 Udemy 课程“Ethereum 和 Solidity：完整的开发人员指南”。
回答by Saensation
There is no direct way to convert an Object Promise into a String.
The only way to continue processing is to call an awaitfunction or use .then()and a callback function.
没有直接的方法可以将 Object Promise 转换为 String。继续处理的唯一方法是调用await函数或使用.then()和回调函数。
