---
# System prepended metadata

title: 80th meeting of TC39

---

# 80th meeting of TC39

- TCQ: https://tcq.app/meeting/BSXq
- Hallway track: https://hubs.mozilla.com/oAAvRHu/tc39
- Agenda: https://github.com/tc39/agendas/blob/master/2021/01.md
- Reflector: https://github.com/tc39/Reflector/issues/340

## Day 1, Monday ([notes](https://mths.be/tc39day1))

<details>
<summary>January 25, 2021, 10:00 to 15:00 PST (UTC -8)</summary>

### 10:00-12:00

- Opening & Welcome - Aki
- Volunteers for note-taking
- Adoption of the agenda
- Approval of the minutes from last meeting
- Secretary's Report
- ECMA262 Status Updates
- ECMA402 Status Updates
- ECMA404 Status Updates
- Test262 Status Updates
- Updates from the CoC Committee
- Confirmation of 2021 Chair Group
- 15m Runtime Semantics for MemberExpression do not conform to web reality, Yulia Startsev & Jason Orendorff
- 30m  RegExp Match Indices update, Ron Buckton

### lunch (60 minutes)

### 13:00-15:00

- 20m JSON modules for stage 3, Myles Borins, Daniel Ehrenberg, Sven Sauleau, Daniel Clark
- 30m Array.isTemplateObject for stage 3, Krzysztof Kotowicz
- 30m 🔒📅 JS Module Blocks for stage 2, Surma
- 30m Class `static` Initialization Blocks for Stage 3 (tentatively), Ron Buckton

</details>

## Day 2 ([notes](https://mths.be/tc39day2))

<details>

<summary>January 26, 2021, 10:00 to 15:00 PST (UTC -8)</summary>

### 10:00-12:00

- 30m `Intl.DateTimeFormat.prototype.formatRange` for Stage 4, Felipe Balbontín 🔒⏰📅
- 30m ResizableArrayBuffer and GrowableSharedArrayBuffer updates, Shu-yu Guo
- 30m Dynamic code brand checks for stage 2, Krzysztof Kotowicz
- 30m Realms updates, Shu-yu Guo (duration & presenter changed per Leo)

### lunch (60 minutes)

### 13:00-15:00

- 30m Intl Locale Info for stage 2, Frank Yung-Fong Tang
- 30m Intl DisplayNames v2 for stage 2, Frank Yung-Fong Tang
- 60m Chartering a Security TG, Michael Ficarra
- 30m `do` expressions for stage 2, Kevin Gibbons
</details>

## Day 3 ([notes](https://mths.be/tc39day3))

<details>

<summary>January 27, 2021, 10:00 to 15:00 PST (UTC -8)</summary>

### 10:00-12:15

- 30m 🔒📅⏰ Temporal updates, Philip Chimento / Ujjwal Sharma
- 20m `async do` expressions for stage 1, Kevin Gibbons
- 45m 🔒📅⏰ class brand check for stage 1, HE Shi-Jun
- 60m 🔒📅⏰ Ergonomic brand checks for private fields for stage 3, Jordan Harband

**_\* we will be going to lunch 15 minutes late_**

### lunch (55 minutes)

### 13:10-15:00

- 20m Extend TimeZoneName Option Proposal for stage 1, Frank Yung-Fong Tang
- 30m Brand checking, Daniel Ehrenberg
- 10m ⌛️ Relative indexing method for stage 4, Shu-yu Guo
- 20m eraDisplay option for Intl.DateTimeFormat for stage 1, Shane F. Carr
- 5m Kevin do-block announcement
- 45m Spec complexity and planning for future implementations, Shane F. Carr


</details>

## Day 4 ([notes](https://mths.be/tc39day4))

<details open>

<summary>January 28, 2021, 10:00 to 15:00 PST (UTC -8)</summary>

### 10:00-12:00

- 20m 🔒📅⏰ Adopting Unicode behavior for set notation in regular expressions, Markus Scherer, Mathias Bynens
- 30m Revisiting `RegExp.escape`, Jordan Harband
- 30m index from end syntax for stage 1, HE Shi-Jun
- 20m 🔒⏰ Array find from last for stage 1, Wenlu Wang
- 30m defer module import eval for stage 1, Yulia Startsev

### lunch (60 minutes)

### 13:00-15:00

- 20m Intl LocaleMatcher for Stage 1, Shane
- 15m Inclusion WG updates and Matrix proposal | Mark Cohen
- 15m Incubation call chartering, Shu-yu Guo
- 30m, ⌛️The nature of protocols in JavaScript, Daniel Ehrenberg

</details>

***

## Overflow

### From agenda



### Timebox overrun

## Schedule constraints

* ☑️ Surma: Only available on the 25th
* ☑️ Felipe Balbontín: Only available on the 26th or on the 27th in the morning.
* ☑️ Mark Cohen: Not available Monday
* ☑️ Mathias Bynens: Only available on the 28th in the morning (for “Adopting Unicode behavior for set notation in regular expressions” agenda item)
* ☑️ Dan Ehrenberg: will miss the first hour of Thursday
* ☑️ Temporal: Only available in morning sessions. Light preference for Wed/Thurs
* ☑️ Wenlu Wang, Hax: Preference for morning sessions.


## emoji legend

_note: this is mostly intended to be information for chairs in the scheduling and re-arrangement process_

- ☑️ - schedule constraints are currently met (remove if schedule changes must be made)
- 🔒 - agenda item is placed intentionally to accomodate schedule constraints
- 📅 - agenda item is constrained by day
- ⏰ - agenda item is constrained by time
- ⏳ - agenda item added after deadline



