|
1 | | -import React from "react"; |
| 1 | +import React,{useState,useEffect} from "react"; |
2 | 2 | import "./styles.css"; |
3 | 3 | import initSqlJs from "sql.js"; |
4 | 4 |
|
5 | | -// Required to let webpack know it needs to copy the wasm file to our assets |
6 | | -import sqlWasm from "!!file-loader?name=sql-wasm-[contenthash].wasm!sql.js/dist/sql-wasm.wasm" |
| 5 | +// Required to let webpack 4 know it needs to copy the wasm file to our assets |
| 6 | +import sqlWasm from "!!file-loader?name=sql-wasm-[contenthash].wasm!sql.js/dist/sql-wasm.wasm"; |
7 | 7 |
|
8 | | -export default class App extends React.Component { |
| 8 | +export default function App() { |
| 9 | + const [db, setDb] = useState(null); |
| 10 | + const [error, setError] = useState(null); |
9 | 11 |
|
10 | | - constructor() { |
11 | | - super(); |
12 | | - this.state = { db: null, err: null, results: null } |
13 | | - } |
14 | | - |
15 | | - componentDidMount() { |
| 12 | + useEffect(async () => { |
16 | 13 | // sql.js needs to fetch its wasm file, so we cannot immediately instantiate the database |
17 | 14 | // without any configuration, initSqlJs will fetch the wasm files directly from the same path as the js |
18 | 15 | // see ../craco.config.js |
19 | | - initSqlJs({ |
20 | | - locateFile: () => sqlWasm // Important |
21 | | - }) |
22 | | - .then(SQL => this.setState({ db: new SQL.Database() })) |
23 | | - .catch(err => this.setState({ err })); |
24 | | - } |
25 | | - |
26 | | - exec(sql) { |
27 | | - let results = null, err = null; |
28 | 16 | try { |
29 | | - // The sql is executed synchronously on the UI thread. |
30 | | - // You may want to use a web worker |
31 | | - results = this.state.db.exec(sql); // an array of objects is returned |
32 | | - } catch (e) { |
33 | | - // exec throws an error when the SQL statement is invalid |
34 | | - err = e |
| 17 | + const SQL = await initSqlJs({ locateFile: () => sqlWasm }); |
| 18 | + setDb(new SQL.Database()); |
| 19 | + } catch (err) { |
| 20 | + setError(err); |
35 | 21 | } |
36 | | - this.setState({ results, err }) |
37 | | - } |
| 22 | + }, []); |
38 | 23 |
|
39 | | - /** |
40 | | - * Renders a single value of the array returned by db.exec(...) as a table |
41 | | - */ |
42 | | - renderResult({ columns, values }) { |
43 | | - return ( |
44 | | - <table> |
45 | | - <thead> |
46 | | - <tr> |
47 | | - {columns.map(columnName => |
48 | | - <td>{columnName}</td> |
49 | | - )} |
50 | | - </tr> |
51 | | - </thead> |
| 24 | + if (error) return <pre>{error.toString()}</pre>; |
| 25 | + else if (!db) return <pre>Loading...</pre>; |
| 26 | + else return <SQLRepl db={db} />; |
| 27 | +} |
52 | 28 |
|
53 | | - <tbody> |
54 | | - {values.map(row => // values is an array of arrays representing the results of the query |
55 | | - <tr> |
56 | | - {row.map(value => |
57 | | - <td>{value}</td> |
58 | | - )} |
59 | | - </tr> |
60 | | - )} |
61 | | - </tbody> |
62 | | - </table> |
63 | | - ); |
64 | | - } |
| 29 | +/** |
| 30 | + * A simple SQL read-eval-print-loop |
| 31 | + * @param {import("sql.js").Database} db |
| 32 | + */ |
| 33 | +function SQLRepl({ db }) { |
| 34 | + const [error, setError] = useState(null); |
| 35 | + const [results, setResults] = useState([]); |
65 | 36 |
|
66 | | - render() { |
67 | | - let { db, err, results } = this.state; |
68 | | - if (!db) return <pre>Loading...</pre>; |
69 | | - return ( |
70 | | - <div className="App"> |
| 37 | + function exec(sql) { |
| 38 | + try { |
| 39 | + // The sql is executed synchronously on the UI thread. |
| 40 | + // You may want to use a web worker here instead |
| 41 | + setResults(db.exec(sql)); // an array of objects is returned |
| 42 | + setError(null); |
| 43 | + } catch (err) { |
| 44 | + // exec throws an error when the SQL statement is invalid |
| 45 | + setError(err); |
| 46 | + setResults([]); |
| 47 | + } |
| 48 | + } |
71 | 49 |
|
72 | | - <h1>React SQL interpreter</h1> |
| 50 | + return ( |
| 51 | + <div className="App"> |
| 52 | + <h1>React SQL interpreter</h1> |
73 | 53 |
|
74 | | - <textarea |
75 | | - onChange={e => this.exec(e.target.value)} |
76 | | - placeholder="Enter some SQL. No inspiration ? Try "select sqlite_version()"" |
77 | | - ></textarea> |
| 54 | + <textarea |
| 55 | + onChange={(e) => exec(e.target.value)} |
| 56 | + placeholder="Enter some SQL. No inspiration ? Try "select sqlite_version()"" |
| 57 | + ></textarea> |
78 | 58 |
|
79 | | - <pre className="error">{(err || "").toString()}</pre> |
| 59 | + <pre className="error">{(error || "").toString()}</pre> |
80 | 60 |
|
81 | | - <pre>{results |
82 | | - ? results.map(this.renderResult) // results contains one object per select statement in the query |
83 | | - : "" |
84 | | - }</pre> |
| 61 | + <pre> |
| 62 | + { |
| 63 | + // results contains one object per select statement in the query |
| 64 | + results.map(({ columns, values }, i) => ( |
| 65 | + <ResultsTable key={i} columns={columns} values={values} /> |
| 66 | + )) |
| 67 | + } |
| 68 | + </pre> |
| 69 | + </div> |
| 70 | + ); |
| 71 | +} |
85 | 72 |
|
86 | | - </div> |
87 | | - ); |
88 | | - } |
| 73 | +/** |
| 74 | + * Renders a single value of the array returned by db.exec(...) as a table |
| 75 | + */ |
| 76 | +function ResultsTable({ columns, values }) { |
| 77 | + return ( |
| 78 | + <table> |
| 79 | + <thead> |
| 80 | + <tr> |
| 81 | + {columns.map((columnName) => ( |
| 82 | + <td>{columnName}</td> |
| 83 | + ))} |
| 84 | + </tr> |
| 85 | + </thead> |
89 | 86 |
|
| 87 | + <tbody> |
| 88 | + { |
| 89 | + // values is an array of arrays representing the results of the query |
| 90 | + values.map((row) => ( |
| 91 | + <tr> |
| 92 | + {row.map((value) => ( |
| 93 | + <td>{value}</td> |
| 94 | + ))} |
| 95 | + </tr> |
| 96 | + )) |
| 97 | + } |
| 98 | + </tbody> |
| 99 | + </table> |
| 100 | + ); |
90 | 101 | } |
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