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https://github.com/vercel-labs/scriptc.git
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Chris Tate
4d3ee3fffd
- Array patterns over strings split by code points via the string-iterator machinery: positions, holes, defaults, rest, nesting, and for-of heads - Destructured stdlib-global members bind their builtin identity tokens with Node-agreeing === identity; aliases register the twin - Surfaced-global members like Math.max fence eagerly by name — a token would quietly degrade them - Object patterns over strings bind length; wrapper-method extraction names the detached method # Conflicts: # packages/compiler/test/ts7/baselines/order-parity.json
64 lines
1.7 KiB
TypeScript
64 lines
1.7 KiB
TypeScript
// Destructuring ASSIGNMENT from string sources — the declaration path's
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// rules against EXISTING bindings: array patterns split code points
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// (astral characters whole), with elisions, defaults behind the bounds
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// test, rest packing the remaining points, and the sole-leading-rest
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// unwrap; object patterns read the wrapper's `length` into identifier,
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// property, and element targets. Empty patterns are pure validation.
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let a = "";
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let b = "";
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let rest: string[] = [];
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[a, b] = "😀x";
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console.log(a, b);
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// Defaults fire exactly past the last code point.
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[a = "A", b = "B"] = "z";
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console.log(a, b);
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// Elision consumes a position without assigning.
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[, b] = "pq";
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console.log(b);
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[a, ...rest] = "p😀r";
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console.log(a, rest.join(","));
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// `[...[x, y]] = s` consumes what the inner pattern alone would.
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[...[a, b]] = "uv";
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console.log(a, b);
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// The assignment expression's VALUE is the source string itself.
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console.log(([a] = "w"));
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let n = 0;
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({ length: n } = "hello");
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console.log(n);
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({ length: n = 42 } = "😀"); // dead default: length always exists
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console.log(n);
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// Property and element targets ride the shared target plumbing.
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const box = { v: 0 };
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({ length: box.v } = "abc");
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console.log(box.v);
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const cells = [0, 0];
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({ length: cells[1] } = "😀😀");
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console.log(cells.join(","));
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// Empty patterns: GetIterator / RequireObjectCoercible, nothing bound.
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[] = "xy";
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({} = "xy");
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// for-of expression heads assign per element.
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for ([a, b = "!"] of ["mn", "😀"]) {
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console.log(a, b);
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}
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for ({ length: n } of ["", "abc"]) {
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console.log(n);
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}
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// A for-of DIRECTLY over a string assigns per code point.
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for ([a] of "c😀") {
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console.log(a);
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}
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for ({ length: n } of "d😀") {
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console.log(n);
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}
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