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refactor: Some optimizations to minified size
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@bradenmacdonald
bradenmacdonald committed Aug 3, 2023
1 parent db6840f commit 1de24e6
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Showing 2 changed files with 61 additions and 73 deletions.
7 changes: 3 additions & 4 deletions CalendarDate.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -153,10 +153,9 @@ Deno.test("fromString()", async (t) => {
}
});

Deno.test("parseTemplateLiteral() can be used to create a date string literal", () => {
const CustomDateLiteral = CalendarDate.parseTemplateLiteral;
Deno.test("D can be used to create a date string literal", () => {
const month = "01";
const obj = CustomDateLiteral`${2000 + 16}-${month}-31`;
const obj = D`${2000 + 16}-${month}-31`;
assertEquals(obj.year, 2016);
assertEquals(obj.toString(), "2016-01-31");
});
Expand Down Expand Up @@ -458,7 +457,7 @@ Deno.test("formatting dates - gives error with non-UTC formatter", () => {
assertThrows(
() => D`2023-08-01`.format(pacificTime),
Error,
"For CalendarDates, Intl.DateTimeFormat must be using UTC timezone.",
"DateTimeFormat must use UTC timezone.",
);
});

Expand Down
127 changes: 58 additions & 69 deletions CalendarDate.ts
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
const MONTHS = Object.freeze({
const freeze = Object.freeze;

const MONTHS = freeze({
JAN: 1,
FEB: 2,
MAR: 3,
Expand All @@ -13,7 +15,7 @@ const MONTHS = Object.freeze({
DEC: 12,
});

const DAYS = Object.freeze({
const DAYS = freeze({
MON: 0,
TUE: 1,
WED: 2,
Expand All @@ -23,8 +25,8 @@ const DAYS = Object.freeze({
SUN: 6,
});

const MONTH_SUMS_NORMAL_YEAR = Object.freeze([
undefined as unknown as number, // we use 1-indexed months, so there's no entry at the zero index.
const MONTH_SUMS_NORMAL_YEAR = freeze([
NaN, // we use 1-indexed months, so there's no entry at the zero index.
0,
31,
59,
Expand All @@ -39,8 +41,8 @@ const MONTH_SUMS_NORMAL_YEAR = Object.freeze([
334,
]);

const MONTH_SUMS_LEAP_YEAR = Object.freeze([
undefined as unknown as number, // we use 1-indexed months, so there's no entry at the zero index.
const MONTH_SUMS_LEAP_YEAR = freeze([
NaN, // we use 1-indexed months, so there's no entry at the zero index.
0,
31,
60,
Expand All @@ -55,26 +57,10 @@ const MONTH_SUMS_LEAP_YEAR = Object.freeze([
335,
]);

/** Character code of the letter A, used for the cached strings below */
const MONTHS_CHAR_OFFSET = "A".charCodeAt(0) - 1;

// The following maps convert from day of the year (e.g. 0 for Jan. 1) to month ('A' = Jan, 'B' = Feb, ...)
// These maps are precomputed to make the date class more efficient.
const NORMAL_YEAR =
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC" +
"DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" +
"GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHIIIIIIIIIIIIIIIIIIIIIIIIIIIIII" +
"JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL";
const LEAP_YEAR =
"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC" +
"DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" +
"GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHIIIIIIIIIIIIIIIIIIIIIIIIIIIIII" +
"JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL";

const DAYS_PER_MONTH = Object.freeze([
undefined, // we use 1-indexed months, so there's no entry at the zero index.
const DAYS_PER_MONTH = freeze([
NaN, // we use 1-indexed months, so there's no entry at the zero index.
/* Jan */ 31,
undefined,
NaN,
/* Mar */ 31,
/* Apr */ 30,
/* May */ 31,
Expand All @@ -87,6 +73,24 @@ const DAYS_PER_MONTH = Object.freeze([
/* Dec */ 31,
]);

/** Character code of the letter A, used for the cached strings below */
const MONTHS_CHAR_OFFSET = "A".charCodeAt(0) - 1;

// The following maps convert from day of the year (e.g. 0 for Jan. 1) to month ('A' = Jan, 'B' = Feb, ...)
// These maps are precomputed to make the date class more efficient.
// const NORMAL_YEAR =
// "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC" +
// "DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF" +
// "GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHIIIIIIIIIIIIIIIIIIIIIIIIIIIIII" +
// "JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL";
// Instead of hard-coding as seen above, we construct these in the following way to improve minification size.
const pre = "A".repeat(31) + "B".repeat(28);
const end = "CDEFGHIJKL".split("").map((x, i) =>
x.repeat(DAYS_PER_MONTH[i + 3])
).join("");
const NORMAL_YEAR = pre + end;
const LEAP_YEAR = pre + "B" + end;

/**
* Internal helper method.
* Given a year, month, and day triplet, return
Expand All @@ -97,17 +101,8 @@ const DAYS_PER_MONTH = Object.freeze([
* @param {number} day - Day (1-31)
*/
function tripletToDaysValue(year: number, month: number, day: number): number {
if (!Number.isInteger(year)) {
throw new Error(`Invalid year value: not an integer.`);
}
if (!Number.isInteger(month)) {
throw new Error(`Invalid month value: not an integer: ${month}`);
}
if (!Number.isInteger(day)) {
throw new Error(`Invalid day value: not an integer.`);
}
if (day <= 0 || day > CalendarDate.daysInMonth(year, month)) { // daysInMonth verifies the year/month range.
throw new Error(`Invalid date argument: day is out of range.`);
throw new Error(`Day out of range.`);
}
let daysValue = (year * 365) + ((year + 3) / 4 | 0) -
((year + 99) / 100 | 0) + ((year + 399) / 400 | 0);
Expand All @@ -122,7 +117,7 @@ function tripletToDaysValue(year: number, month: number, day: number): number {
/**
* A calendar date, using the Gregorian calendar. Does not have any time component.
*/
export class CalendarDate {
class CalendarDate {
/** The internal date value (days since 0000-01-01) */
readonly #value: number;

Expand All @@ -141,41 +136,30 @@ export class CalendarDate {
* @param {string} str - An ISO 8601 date string
*/
public static fromString(str: string): CalendarDate {
const year = parseInt(str.substring(0, 4), 10);
/** Helper to get an int from a substring of a string, defaulting to two digits long. */
const extractInt = (someString: string, start: number, end?: number) =>
parseInt(someString.substring(start, end ?? start + 2), 10);
const year = extractInt(str, 0, 4);
let month = NaN;
let day = NaN;
if (str.length === 10 && str.charAt(4) === "-" && str.charAt(7) === "-") {
// YYYY-MM-DD format, presumably:
month = parseInt(str.substring(5, 7), 10);
day = parseInt(str.substring(8, 10), 10);
month = extractInt(str, 5);
day = extractInt(str, 8);
} else if (
str.length === 8 && String(parseInt(str, 10)).padStart(8, "0") === str
) {
// YYYYMMDD format, presumably.
// (Note we check 'String(parseInt(str, 10)).padStart(8, "0") === str' to avoid matching things like '05/05/05')
month = parseInt(str.substring(4, 6), 10);
day = parseInt(str.substring(6, 8), 10);
month = extractInt(str, 4);
day = extractInt(str, 6);
}
if (isNaN(year) || isNaN(month) || isNaN(day)) {
throw new Error("Date string not in YYYY-MM-DD or YYYYMMDD format");
}
return new CalendarDate(tripletToDaysValue(year, month, day));
}

/**
* Parse a template string literal.
* e.g. const D = CalendarDate.parseTemplateLiteral; const date1 = D`2016-01-01`;
*
* @param {Object} strings Well-formed template call site object
* @param {...*} keys - substitution values
*/
public static parseTemplateLiteral(
strings: TemplateStringsArray,
...keys: unknown[]
): CalendarDate {
return CalendarDate.fromString(String.raw(strings, ...keys));
}

/**
* Get the current date, according to the system's local time
*/
Expand All @@ -200,6 +184,8 @@ export class CalendarDate {
daysValue > 3652424 // 1096100 is Dec. 31, 9999
) {
throw new Error(`Date value (${daysValue}) out of range.`);
} else if (!Number.isInteger(daysValue)) {
throw new Error(`Non-integer date value.`);
}
this.#value = daysValue;
}
Expand Down Expand Up @@ -277,12 +263,6 @@ export class CalendarDate {
* @param {number} month - Month (1-12)
*/
public static daysInMonth(year: number, month: number): number {
if (
!(year >= 1 && year <= 9999) ||
!(month >= MONTHS.JAN && month <= MONTHS.DEC)
) {
throw new Error(`Invalid year or month value. (${year}-${month})`);
}
if (month === MONTHS.FEB) {
return CalendarDate.isLeapYear(year) ? 29 : 28;
}
Expand Down Expand Up @@ -323,9 +303,7 @@ export class CalendarDate {
public static fromDate(d: Date): CalendarDate {
const isoString = d.toISOString();
if (!isoString.endsWith("00:00:00.000Z")) {
throw new Error(
`Do not use non-UTC Date() instances for calendar dates (${isoString})`,
);
throw new Error(`Non-UTC Date. Use UTC for calendar dates.`);
}
return new CalendarDate(
tripletToDaysValue(
Expand Down Expand Up @@ -365,9 +343,7 @@ export class CalendarDate {

public format(formatter: Intl.DateTimeFormat): string {
if (formatter.resolvedOptions().timeZone !== "UTC") {
throw new Error(
"For CalendarDates, Intl.DateTimeFormat must be using UTC timezone.",
);
throw new Error("DateTimeFormat must use UTC timezone.");
}
return formatter.format(this.toEpochMs()); // This is _slightly_ faster than using formatter .format(this.toDate())
}
Expand Down Expand Up @@ -402,5 +378,18 @@ export class CalendarDate {
}
}

/** Convenience method for writing calendar dates */
export const D = CalendarDate.parseTemplateLiteral;
/**
* Parse a template string literal as an ISO 8601 calendar date.
* e.g. const date = D`2016-01-01`;
*
* @param {Object} strings Well-formed template call site object
* @param {...*} keys - substitution values
*/
const D = (
strings: TemplateStringsArray,
...keys: unknown[]
): CalendarDate => {
return CalendarDate.fromString(String.raw(strings, ...keys));
};

export { CalendarDate, D };

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