JavaScript syntax overview

The

script only modifies the current configuration copy and does not directly modify the original subscription text.

生成一个符合 YumeBox 运行时约束的 JavaScript 覆写

Execution process

Initialize runtime

Initializes the JavaScript runtime and built-in methods the first time a .js file appears in the current override chain.

Pass in configuration object

The current configuration is converted to a JavaScript object and passed in as the profile parameter.

execute main

The script can modify profile directly or return a new configuration object. Both synchronous return values and completed Promises are supported.

Check return value

The return value must be convertible to a JSON object. Script errors, missing main, or returning non-object values will stop the current override chain.

The same override chain reuses the JavaScript runtime, but each script executes in an isolated scope; the main, variables, and declarations of the previous script are not leaked to the next script.

`main(profile)`

Minimal script

最小覆写.js

function main(profile) {
  return profile;
}

Modify fields

修改字段.js

function main(profile) {
  profile["log-level"] = "info";
  profile["mixed-port"] = 7890;
  return profile;
}

expected diff

修改字段 diff.js

function main(profile) {
-  profile["log-level"] = "info"; 
+  profile["log-level"] = "debug"; 
  return profile;
}

// [!code --] and // [!code ++] are only used for diff display in documentation and are legal JavaScript comments themselves.

Condition modification

按模式修改.js

function main(profile) {
  if (profile.mode === "global") {
    profile["log-level"] = "warning";
  }
  return profile;
}

Asynchronous script

异步 main.js

async function main(profile) {
  await Promise.resolve();
  profile.extra = "ready";
  return profile;
}

Promise must eventually complete; it will return async main(profile) did not settle when it is pending.

Return value requirements

return value	result
Configuration object	Success, hand over to next overwrite.
Promise completed with result object	success.
Array, string, number, boolean, `null` or `undefined`	Failure: `JS override result must be an object`.
Object that cannot be converted to JSON	Fails and stops compilation.

Error example:

错误的返回值.js

function main(profile) {
  return profile.rules;
}

If profile.rules is an array, the script will fail instead of continuing with the array as a complete configuration.

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JavaScript syntax overview

Execution process

`main(profile)`

Minimal script

Modify fields

expected diff

Condition modification

Asynchronous script

Return value requirements

​Execution process

​main(profile)

​Minimal script

​Modify fields

​expected diff

​Condition modification

​Asynchronous script

​Return value requirements

Execution process

`main(profile)`

Minimal script

Modify fields

expected diff

Condition modification

Asynchronous script

Return value requirements