42 lines
944 B
TypeScript
42 lines
944 B
TypeScript
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// https://github.com/andreypopp/autobind-decorator
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/**
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* Return a descriptor removing the value and returning a getter
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* The getter will return a .bind version of the function
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* and memoize the result against a symbol on the instance
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*/
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export function bindThis(target, key, descriptor) {
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let fn = descriptor.value;
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if (typeof fn !== 'function') {
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throw new TypeError(`@bindThis decorator can only be applied to methods not: ${typeof fn}`);
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}
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return {
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configurable: true,
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get() {
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// eslint-disable-next-line no-prototype-builtins
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if (this === target.prototype || this.hasOwnProperty(key) ||
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typeof fn !== 'function') {
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return fn;
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}
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const boundFn = fn.bind(this);
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Object.defineProperty(this, key, {
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configurable: true,
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get() {
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return boundFn;
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},
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set(value) {
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fn = value;
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delete this[key];
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},
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});
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return boundFn;
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},
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set(value) {
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fn = value;
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},
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};
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}
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