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Ergonomic brand checks for private fields

Category

JavaScript

Type

Chromium catches up

Status

Enabled by default (Chrome 91)

Intent stage

Start prototyping

Summary

This JavaScript feature adds the capability for testing the existence of a private field in an object: "#foo in obj" Proposal: https://github.com/tc39/proposal-private-fields-in-in The feature has reached Stage 3 in TC39.

Motivation

See proposal https://github.com/tc39/proposal-private-fields-in-in for motivating examples.

Standards & signals

• Specification: https://github.com/tc39/proposal-private-fields-in-in
• Firefox: No signal — This is a minor, uncontroversial TC39 stage 3 feature.
• Safari: No signal — This is a minor, uncontroversial TC39 stage 3 feature.
• Web developers: No signals — N/A. This is a minor, uncontroversial TC39 stage 3 feature.
• Tracking bug: https://bugs.chromium.org/p/v8/issues/detail?id=11374

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