Created
July 13, 2015 20:44
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Simple pagination algorithm
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// Implementation in ES6 | |
function pagination(c, m) { | |
var current = c, | |
last = m, | |
delta = 2, | |
left = current - delta, | |
right = current + delta + 1, | |
range = [], | |
rangeWithDots = [], | |
l; | |
for (let i = 1; i <= last; i++) { | |
if (i == 1 || i == last || i >= left && i < right) { | |
range.push(i); | |
} | |
} | |
for (let i of range) { | |
if (l) { | |
if (i - l === 2) { | |
rangeWithDots.push(l + 1); | |
} else if (i - l !== 1) { | |
rangeWithDots.push('...'); | |
} | |
} | |
rangeWithDots.push(i); | |
l = i; | |
} | |
return rangeWithDots; | |
} | |
/* | |
Test it: | |
for (let i = 1, l = 20; i <= l; i++) | |
console.log(`Selected page ${i}:`, pagination(i, l)); | |
Expected output: | |
Selected page 1: [1, 2, 3, "...", 20] | |
Selected page 2: [1, 2, 3, 4, "...", 20] | |
Selected page 3: [1, 2, 3, 4, 5, "...", 20] | |
Selected page 4: [1, 2, 3, 4, 5, 6, "...", 20] | |
Selected page 5: [1, 2, 3, 4, 5, 6, 7, "...", 20] | |
Selected page 6: [1, "...", 4, 5, 6, 7, 8, "...", 20] | |
Selected page 7: [1, "...", 5, 6, 7, 8, 9, "...", 20] | |
Selected page 8: [1, "...", 6, 7, 8, 9, 10, "...", 20] | |
Selected page 9: [1, "...", 7, 8, 9, 10, 11, "...", 20] | |
Selected page 10: [1, "...", 8, 9, 10, 11, 12, "...", 20] | |
Selected page 11: [1, "...", 9, 10, 11, 12, 13, "...", 20] | |
Selected page 12: [1, "...", 10, 11, 12, 13, 14, "...", 20] | |
Selected page 13: [1, "...", 11, 12, 13, 14, 15, "...", 20] | |
Selected page 14: [1, "...", 12, 13, 14, 15, 16, "...", 20] | |
Selected page 15: [1, "...", 13, 14, 15, 16, 17, "...", 20] | |
Selected page 16: [1, "...", 14, 15, 16, 17, 18, 19, 20] | |
Selected page 17: [1, "...", 15, 16, 17, 18, 19, 20] | |
Selected page 18: [1, "...", 16, 17, 18, 19, 20] | |
Selected page 19: [1, "...", 17, 18, 19, 20] | |
Selected page 20: [1, "...", 18, 19, 20] | |
*/ |
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Another Pagination which ensures a fixed number of items in the pagination array, including ellipses as necessary same as material UI pagination.