getDisplayed vs. parseEdited


hard canonical

Canonical values are used by the computer. The format of canonical values is fixed and rigid. These are the values that are persisted in RethinkDB.

In computer science, canonicalization (sometimes standardization or normalization) is a process for converting data that has more than one possible representation into a “standard”, “normal”, or canonical form. This can be done to compare different representations for equivalence, to count the number of distinct data structures, to improve the efficiency of various algorithms by eliminating repeated calculations, or to make it possible to impose a meaningful sorting order.

Generally, canonical values are string, except for number and integer, which use JS native types. For each type, the string containing the canonical value respects a precise syntax (see tests in lib/xcraft-core-converters/test for documentation).

Examples of canonical values:

Type Example
date "2020-03-31"
time "11:30:00"
datetime "2019-01-18T23:59:59.000Z"
price "100", "49.95"
delay "* * * 30 * * *" (30 days)
color "#FF000" (red in rgb), "HSL(40,100,100)", "CMYK(100,0,0,50)", G(50) ( medium gray)

number and integer use JS native types:

Type Example
number 50, 0.02
integer 450, -3

The function parseEdited(edited) parse a free text entered by the user. Some flexibility allows the user to enter data in various formats, possibly incomplete, with a minimum of intelligence. For example:

Type Example
date parseEdited("25")"2020-03-25" (completed by current month and year)
time parseEdited("12")"12:00:00" (completed with zeros)
delay parseEdited("20j")"* * * 20 * * *"
delay parseEdited("4h")"* * 4 * * * *"
color parseEdited("#12F")"#1122FF"

The function parseEdited return a map with {value, error}. If everything is ok, error === null. In the event of an error, the value comes as close as possible to something plausible.


soft displayed

Displayed values are for human users. A displayed value has several possible representations, more or less long, to adapt to different situations in the UI.

The function getDisplayed(canonical, format) format a canonical value to a string for the human user (the parameter format is optional). For example:

Type Example
date getDisplayed("2020-03-31")"31.03.2020"
date getDisplayed("2020-03-31", "dMy")"31 mars 2020" (with parameter format)

See in lib/xcraft-core-converters/lib for documentation of each type.

Many types

There are many types, for all uses:

Type Use Canonical Displayed
date A date with day, month and year. "2020-03-31" "31.03.2020" "31 mars 2020" "Mardi 31 mars 2020"
time A time with hours, minutes and seconds. "13:20:30" "13:20"
"01:30:45" "1 heure 30"
datetime A date and time. "2019-01-18T12:48:00.000Z" "18.01.2019 12:48"
number A real number, therefore with a fractional part. 2.003 "2.003"
integer An integer, therefore without fractional part. 45 "45"
price A price in Swiss francs, with 2 decimal places for cents (use big numbers). "29.9" "29.90"
percent A percentage in range [0..1]. "0.52" "52%"
delay A duration in minutes, hours, days, months or years. "* * 4 * * * *" "4h"
"* * * 3.5 * * *" "3.5j"
length A length in meters (displayed in “km”, “m”, “cm” or “mm”). "0.045" "0.045m" "4.5cm" "45mm"
weight A weight in kilogram (displayed in “t”, “kg”, “g” or “mg”). "0.123" "0.123kg" "123g"
volume A volume defined by 3 lengths in meters (displayed in “m”, “cm” or “mm”). "0.12 0.13 1.4" "12 × 13 × 140 cm"
A volume defined by 1 value in meters (displayed in “l” or “dm3”). "0.012" "12dm3" "12l"
The function getDisplayedIATA format a dimensional weight. "1 1 1" "167kg"
color A color in various color space (RGB, HSL, CMYK or gray scale). "#FF0000" "#FF0000"
"CMYK(0,0,0,0)" "CMYK(0,0,0,0)"

Common mistakes

To get today’s canonical date, don’t do this:

const canonicalNow = date.now();

Instead, write this:

const canonicalNow = DateConverters.getNowCanonical();

Or, to display the current date in plain text:

const displayedNow = DateConverters.getDisplayed(