我想在 PWA 服务工作者中使用 sql-wasm.js ( https://github.com/sql-js/sql.js )。我想使用它的原因是,通过 service-worker 获取 mbtiles(基于 sqlite 的 web 地图图块分布格式),从中提取 web 地图图块图像并将它们存储到索引数据库中。所以我想将 sql-wasm.js 用于纯只读用例。
我从我的服务人员那里调用 sql-wasm.js,如下所示:
import initSqlJs from "./sql-wasm";
import "./sql-wasm.wasm";
...
initSqlJs({}).then(SQL => {
//Create the database
var db = new SQL.Database();
// Run a query without reading the results
db.run("CREATE TABLE test (col1, col2);");
// Insert two rows: (1,111) and (2,222)
db.run("INSERT INTO test VALUES (?,?), (?,?)", [1,111,2,222]);
// Prepare a statement
var stmt = db.prepare("SELECT * FROM test WHERE col1 BETWEEN $start AND $end");
stmt.getAsObject({$start:1, $end:1}); // {col1:1, col2:111}
// Bind new values
stmt.bind({$start:1, $end:2});
while(stmt.step()) { //
var row = stmt.getAsObject();
console.log('Here is a row: ' + JSON.stringify(row));
}
});
...
我的 webpack-config 包括:
externals: { fs: 'fs', }
准备好这些之后,我运行 webpack (4.41.6),然后我收到了这个警告
WARNING in ./src/weiwudi_gw_logic.js 78:2-11
"export 'default' (imported as 'initSqlJs') was not found in './sql-wasm'
@ ./src/weiwudi_gw.js
@ ./test/src/sw_npm.js
和这些错误:
ERROR in ./src/sql-wasm.wasm
Module not found: Error: Can't resolve 'a' in 'F:\github\Weiwudi\src'
@ ./src/sql-wasm.wasm
@ ./src/weiwudi_gw_logic.js
@ ./src/weiwudi_gw.js
@ ./test/src/sw_npm.js
ERROR in ./src/sql-wasm.wasm
WebAssembly module is included in initial chunk.
This is not allowed, because WebAssembly download and compilation must happen asynchronous.
Add an async splitpoint (i. e. import()) somewhere between your entrypoint and the WebAssembly module:
* ./test/src/sw_npm.js --> ./src/weiwudi_gw.js --> ./src/weiwudi_gw_logic.js --> ./src/sql-wasm.wasm
如何避免这些错误/警告?
======
我已经从这张票中获得了信息(尝试了解如何通过 webpack 导入 web-assembly 包),但添加 Experiments/asyncWebAssembly 选项仅适用于 webpack5。如果可能的话,我想用 webpack4 解决这个问题。这是不可能的吗?