server: revert and use a global shim

Author: koush

server/src/rpc-peer-eval.ts

@@ -4,19 +4,25 @@ export interface CompileFunctionOptions {
     filename?: string;
 }
 
-function compileFunction(code: string, params?: ReadonlyArray<string>, options?: CompileFunctionOptions): any {
-    params = params || [];
-    if (options?.filename)
-        code = `${code}\n//# sourceURL=${options.filename}\n`;
-    const f = `(function(${params.join(',')}) {;${code}\n;})`;
-    return eval(f);
+function compileFunction(): any {
+    // this is a hacky way of preventing the closure from capturing the code variable which may be a large blob.
+    try {
+        // "new Function" can't be used because it injects newlines per parameter.
+        // this causes source mapping to get misaligned.
+        return eval((globalThis as any).compileFunctionShim);
+    }
+    finally {
+        delete (globalThis as any).compileFunctionShim;
+    }
 }
 
 export function evalLocal<T>(peer: RpcPeer, script: string, filename?: string, coercedParams?: { [name: string]: any }): T {
     const params = Object.assign({}, peer.params, coercedParams);
-    const f = compileFunction(script, Object.keys(params), {
-        filename,
-    });
+    let code = script;
+    if (filename)
+        code = `${code}\n//# sourceURL=${filename}\n`;
+    (globalThis as any).compileFunctionShim = `(function(${Object.keys(params).join(',')}) {;${code}\n;})`;
+    const f = compileFunction();
     const value = f(...Object.values(params));
     return value;
 }