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more on numbers...

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Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>
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Alex A. Naanou 2023-06-19 19:54:54 +03:00
parent ee6471a627
commit 9125af6047
1 changed files with 21 additions and 10 deletions
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31
js-types-n-oop.js
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@ -26,16 +26,17 @@
// //
// Imagine an apple, it's a "thing" that is an "apple", or we say that // Imagine an apple, it's a "thing" that is an "apple", or we say that
// it has a value "apple". There are lots of apples in the world, // it has a value "apple". There are lots of apples in the world,
// each one is different but all are apples. Now imagine two people, // each one is slightly different but all are apples. Now imagine two
// each looking at an apple, we can say that each person sees the value // people, each looking at an apple, we can say that each person sees
// "apple", those values are equal, and if those people are sitting at // the value "apple", those values are equal, and if those people are
// the same table and looking at the same apple, we say that their // sitting at the same table and looking at the same apple, we say that
// apples are the same, or they are of the same identity, (i.e. the // their apples are the same apple, or in JavaScript-ish, they are of
// same apple). // the same identity.
// Then if we can take a different set of people looking at apples, but // Then if we can take a different set of people looking at apples, but
// now each one has their own personal apple, the values are still the // now each one has their own personal apple, the values are still the
// same, both apples are still apples but now they are different apples, // same, both apples are still looking at apples but now their apples
// aren't they? And thus we say they are of different identities. // are different, aren't they? And thus we say they are of different
// identities.
// We'll come back to this concept a bit later, once we introduce // We'll come back to this concept a bit later, once we introduce
// JavaScript values and types. // JavaScript values and types.
// //
@ -49,7 +50,7 @@
// //
// Note that all numbers are of the same "type", this is different to // Note that all numbers are of the same "type", this is different to
// allot of other languages where numbers are represented closer to the // allot of other languages where numbers are implemented closer to the
// low-level hardware implementation and thus are represented by a // low-level hardware implementation and thus are represented by a
// whole range of number types. // whole range of number types.
// //
@ -58,12 +59,20 @@
var oct = 052 var oct = 052
var hex = 0xFF var hex = 0xFF
var dec = 42 var dec = 42
var exp = .42e2
// //
// But note that these are just different notations and all of the // But note that these are just different notations and all of the
// above resolve to the same number. // above resolve to the same number.
// //
// Numbers also have several limitations:
//
// - precision, rounding errors and fractions (IEEE-754)
0.1 + 0.2 == 0.3 // -> false
// - large number rounding
// Strings // Strings
var string = 'string' var string = 'string'
@ -75,10 +84,12 @@
// XXX a note on template strings // XXX a note on template strings
// Boolieans
// Booleans
var t = true var t = true
var f = false var f = false
// Nulls // Nulls
var n = null var n = null
var u = undefined var u = undefined