feat: add function to wrap block_timestamp in PlainDateTime object

[ashutoshvarma]

Summary

assemblyscript-temporal is tc39-temporal based featureful datetime assemblyscipt library.

This PR integrates the above library with near-sdk-as.

Changes

This PR introduces a new namespace datetime which has block_datetime() function.

block_datetime() - Current block date time. Returns PlainDateTime object initializes with current block timestamp.

Example

import { datetime } from "near-sdk-as";
import { PlainDateTime } from "assemblyscript-temporal";

const blk_time = datetime.block_datetime();
// log(blk_time.toString());  // 2021-04-11T12:52:12.3425805

const blk_time_after_1hr = blk_time.add({ hour: 1 });
// log(blk_time.toString());  // 2021-04-11T13:52:12.3425805

Additional Notes
Temporarily we need to use this ugly import to access UTC getter methods on Date.
https://github.com/ashutoshvarma/near-sdk-as/blob/3070ae69852e5376236ae1bc7cef6f74a3bc1ac8/sdk-core/assembly/datetime.ts#L6

But once this PR AssemblyScript/assemblyscript#1768 is merged, then it can be safely removed.

[ashutoshvarma]

This is weird 🤔
For some reason, a full temporal library is included in every wat.

FAIL __tests__/empty.spec.ts
info Visit https://yarnpkg.com/en/docs/cli/workspaces for documentation about this command.
  ● empty wat › should be mostly empty
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

    expect(received).toBe(expected) // Object.is equality

    - Expected  -   3
    + Received  + 702

      (module
    -  (memory $0 0)
    -  (table $0 1 funcref)
    -  (export "memory" (memory $0))
    +  (type $i32_i32_=>_none (func (param i32 i32)))
    +  (type $none_=>_none (func))
    +  (type $i32_i32_=>_i32 (func (param i32 i32) (result i32)))
    +  (type $i32_i32_i32_=>_none (func (param i32 i32 i32)))
    +  (type $i32_=>_none (func (param i32)))
    +  (type $i32_i32_i32_i32_=>_none (func (param i32 i32 i32 i32)))
    +  (type $i32_=>_i32 (func (param i32) (result i32)))
    +  (type $i32_i32_i32_=>_i32 (func (param i32 i32 i32) (result i32)))
    +  (import "env" "abort" (func $~lib/builtins/abort (param i32 i32 i32 i32)))
    +  (memory $0 1)
    +  (data (i32.const 12) ",\00\00\00\00\00\00\00\00\00\00\00\01\00\00\00\1c\00\00\00I\00n\00v\00a\00l\00i\00d\00 \00l\00e\00n\00g\00t\00h\00")
    +  (data (i32.const 60) ",\00\00\00\00\00\00\00\00\00\00\00\01\00\00\00\1a\00\00\00~\00l\00i\00b\00/\00a\00r\00r\00a\00y\00.\00t\00s\00\00\00")
    +  (data (i32.const 108) "<\00\00\00\00\00\00\00\00\00\00\00\01\00\00\00(\00\00\00A\00l\00l\00o\00c\00a\00t\00i\00o\00n\00 \00t\00o\00o\00 \00l\00a\00r\00g\00e\00\00\00\00\00")
    +  (data (i32.const 172) "<\00\00\00\00\00\00\00\00\00\00\00\01\00\00\00\1e\00\00\00~\00l\00i\00b\00/\00r\00t\00/\00s\00t\00u\00b\00.\00t\00s\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00")
    +  (table $0 1 funcref)
    +  (global $~lib/assemblyscript-temporal/constants/MILLIS_PER_DAY i32 (i32.const 86400000))
    +  (global $~lib/assemblyscript-temporal/constants/MILLIS_PER_HOUR i32 (i32.const 3600000))
    +  (global $~lib/assemblyscript-temporal/constants/MILLIS_PER_MINUTE i32 (i32.const 60000))
    +  (global $~lib/assemblyscript-temporal/constants/MILLIS_PER_SECOND i32 (i32.const 1000))
    +  (global $~lib/assemblyscript-temporal/constants/MICROS_PER_SECOND i32 (i32.const 1000000))
    +  (global $~lib/assemblyscript-temporal/constants/NANOS_PER_SECOND i32 (i32.const 1000000000))
    +  (global $~lib/assemblyscript-temporal/utils/YEAR_MIN i32 (i32.const -271821))
    +  (global $~lib/assemblyscript-temporal/utils/YEAR_MAX i32 (i32.const 275760))
    +  (global $~lib/assemblyscript-temporal/utils/__null (mut i32) (i32.const 0))
    +  (global $~lib/rt/stub/startOffset (mut i32) (i32.const 0))
    +  (global $~lib/rt/stub/offset (mut i32) (i32.const 0))
    +  (global $~lib/ASC_SHRINK_LEVEL i32 (i32.const 0))
    +  (global $~lib/assemblyscript-regex/parser/node/emptyNodeArray (mut i32) (i32.const 0))
    +  (global $~lib/assemblyscript-regex/parser/node/_id (mut i32) (i32.const 0))
    +  (global $~lib/assemblyscript-regex/nfa/matcher/_flags (mut i32) (i32.const 0))
    +  (global $~lib/assemblyscript-regex/nfa/matcher/LOWERCASE_LETTERS (mut i32) (i32.const 0))
    +  (global $~lib/assemblyscript-regex/nfa/matcher/UPPERCASE_LETTERS (mut i32) (i32.const 0))
    +  (global $~lib/assemblyscript-regex/nfa/matcher/UPPER_LOWER_OFFSET i32 (i32.const 32))
    +  (global $~lib/assemblyscript-regex/nfa/nfa/MatchResult.Match i32 (i32.const 0))
    +  (global $~lib/assemblyscript-regex/nfa/nfa/MatchResult.Fail i32 (i32.const 1))
    +  (global $~lib/assemblyscript-regex/nfa/nfa/MatchResult.Ignore i32 (i32.const 2))
    +  (global $~lib/assemblyscript-regex/nfa/nfa/_stateId (mut i32) (i32.const 0))
    +  (global $~lib/assemblyscript-regex/parser/walker/QUANTIFIER_LIMIT i32 (i32.const 1000))
    +  (global $~lib/assemblyscript-regex/regexp/gm (mut i32) (i32.const 0))
    +  (global $../node_modules/assemblyscript-temporal/assembly/constants/MILLIS_PER_DAY i32 (i32.const 86400000))
    +  (global $../node_modules/assemblyscript-temporal/assembly/constants/MILLIS_PER_HOUR i32 (i32.const 3600000))

[ashutoshvarma]

empty.spec.ts is failing due to global variables exposed in assemblyscript-temporal and assemblyscript-regex.
Here are the PRs which decorate the global variables with @lazy to fix this

• decorate all global variables with @lazy ColinEberhardt/assemblyscript-temporal#40
• decorate all global variable with @lazy ColinEberhardt/assemblyscript-regex#41

Once these are merged, the test should pass, for now, it is disabled with xit

[willemneal]

LGTM, just a small nit in the comment.