mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-11-02 07:43:42 +08:00
Chris Tate
b319186a68
A JavaScript function assigned to process.stdout.write or process.stderr.write takes its parameters from the call, not from Node's overloads, but the lowering returned before giving the function its arguments slot. `arguments.length` then folded to the declared parameter count (3 for `function (chunk, encoding, callback)` called with one argument, 0 for a function without parameters), and reading `arguments[i]` was refused at run time. The replacement now receives the call's arguments, so `arguments` holds what the caller passed, as in Node.
44 lines
1.5 KiB
JavaScript
44 lines
1.5 KiB
JavaScript
// A replaced process.stdout.write or process.stderr.write sees the call's own
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// arguments: arguments.length is the number the caller passed, whatever the
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// replacement declares.
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const seen = [];
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const originalOut = process.stdout.write;
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process.stdout.write = function (chunk, encodingOrCallback, callback) {
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seen.push(`stdout declared3 ${arguments.length} ${typeof callback}`);
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return true;
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};
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process.stdout.write("one");
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process.stdout.write("two", "utf8");
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process.stdout.write("three", "utf8", () => {});
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process.stdout.write = function () {
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seen.push(`stdout declared0 ${arguments.length} ${arguments[0]}`);
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return true;
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};
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process.stdout.write("zero");
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process.stdout.write = function (chunk) {
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seen.push(`stdout declared1 ${arguments.length} ${arguments[1]}`);
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return true;
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};
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process.stdout.write("a", "latin1");
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process.stdout.write = originalOut;
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const originalErr = process.stderr.write;
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process.stderr.write = function (chunk, encodingOrCallback, callback) {
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seen.push(`stderr declared3 ${arguments.length} ${typeof callback}`);
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return true;
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};
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process.stderr.write("one");
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process.stderr.write("two", "utf8");
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process.stderr.write("three", "utf8", () => {});
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process.stderr.write = function () {
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seen.push(`stderr declared0 ${arguments.length} ${arguments[0]}`);
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return true;
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};
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process.stderr.write("zero");
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process.stderr.write = function (chunk) {
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seen.push(`stderr declared1 ${arguments.length} ${arguments[1]}`);
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return true;
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};
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process.stderr.write("a", "latin1");
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process.stderr.write = originalErr;
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console.log(seen.join("\n"));
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