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Simple pagination with three dots
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function Pagination(countPages, maxLength) { | |
if (maxLength < 5) return; | |
if (countPages < maxLength) maxLength = countPages; | |
this.countPages = countPages; | |
this.maxLength = maxLength; | |
this.currentLength = 0; | |
this.currentPage = this.firstPage = 1; | |
this.lastPage = this.countPages; | |
this.pages = []; | |
} | |
Pagination.prototype.setCurrentPage = function(number) { | |
if (number <= this.countPages) | |
this.currentPage = number; | |
return this; | |
}; | |
Pagination.prototype.generate = function() { | |
this.pages = (new Array(this.countPages)).fill(null); | |
this.currentLength = 0; | |
this.stretchWith(this.firstPage); | |
this.stretchWith(this.lastPage); | |
this.stretchWith(this.currentPage); | |
var delta = 1; | |
while (true) { | |
if (this.stretchWith(this.currentPage - delta)) break; | |
if (this.stretchWith(this.currentPage + delta)) break; | |
delta++; | |
if (this.currentPage - delta <= this.firstPage && this.currentPage + delta >= this.lastPage) break; | |
} | |
return this.pages.join(' ').replace(/\s\s+/g, ' ... ').split(' '); | |
}; | |
Pagination.prototype.stretchWith = function(pageNumber) { | |
if (this.pages[pageNumber - 1] === null) { | |
this.pages[pageNumber - 1] = pageNumber; | |
this.currentLength++; | |
} | |
return this.currentLength === this.maxLength; | |
}; | |
/* | |
* Tests: | |
* (new Pagination(100, 10)).setCurrentPage(1).generate() -> ["1", "2", "3", "4", "5", "6", "7", "8", "9", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(5).generate() -> ["1", "2", "3", "4", "5", "6", "7", "8", "9", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(17).generate() -> ["1", "...", "13", "14", "15", "16", "17", "18", "19", "20", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(24).generate() -> ["1", "...", "20", "21", "22", "23", "24", "25", "26", "27", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(49).generate() -> ["1", "...", "45", "46", "47", "48", "49", "50", "51", "52", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(66).generate() -> ["1", "...", "62", "63", "64", "65", "66", "67", "68", "69", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(78).generate() -> ["1", "...", "74", "75", "76", "77", "78", "79", "80", "81", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(81).generate() -> ["1", "...", "77", "78", "79", "80", "81", "82", "83", "84", "...", "100"] | |
* (new Pagination(100, 10)).setCurrentPage(100).generate() -> ["1", "...", "92", "93", "94", "95", "96", "97", "98", "99", "100"] | |
*/ |
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