fix(zone.js): read Symbol.species safely#45369
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arturovt wants to merge 1 commit intoangular:masterfrom
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fix(zone.js): read Symbol.species safely#45369arturovt wants to merge 1 commit intoangular:masterfrom
Symbol.species safely#45369arturovt wants to merge 1 commit intoangular:masterfrom
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@arturovt , thank you for the PR, could you add a test case around here ? |
JiaLiPassion
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Mar 17, 2022
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Need to add test case
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We must read `Symbol.species` safely because `this` may be anything. For instance, `this` may be an object without a prototype (created through `Object.create(null)`); thus `this.constructor` will be undefined. One of the use cases is SystemJS creating prototype-less objects (modules) via `Object.create(null)`. The SystemJS creates an empty object and copies promise properties into that object (within the `getOrCreateLoad` function). The zone.js then checks if the resolved value has the `then` method and invokes it with the `value` context. Otherwise, this will throw an error: `TypeError: Cannot read properties of undefined (reading 'Symbol(Symbol.species)')`.
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@arturovt @JiaLiPassion Is this ready to be merged? |
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@dylhunn , yes, this one is ready to merge, thank you. |
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This PR was merged into the repository by commit e2eaac3. |
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We must read `Symbol.species` safely because `this` may be anything. For instance, `this` may be an object without a prototype (created through `Object.create(null)`); thus `this.constructor` will be undefined. One of the use cases is SystemJS creating prototype-less objects (modules) via `Object.create(null)`. The SystemJS creates an empty object and copies promise properties into that object (within the `getOrCreateLoad` function). The zone.js then checks if the resolved value has the `then` method and invokes it with the `value` context. Otherwise, this will throw an error: `TypeError: Cannot read properties of undefined (reading 'Symbol(Symbol.species)')`. PR Close #45369
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We must read
Symbol.speciessafely becausethismay be anything. For instance,thismay be an object without a prototype (created through
Object.create(null)); thusthis.constructorwill be undefined. One of the use cases is SystemJS creatingprototype-less objects (modules) via
Object.create(null). The SystemJS creates an emptyobject and copies promise properties into that object (within the
getOrCreateLoadfunction). The zone.js then checks if the resolved value has the
thenmethod and invokesit with the
valuecontext. Otherwise, this will throw an error:TypeError: Cannot read properties of undefined (reading 'Symbol(Symbol.species)').PR Checklist
PR Type
Does this PR introduce a breaking change?