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'use strict';
var _ = require('lodash');
var chalk = require('chalk');
/**
* The paginator keeps track of a pointer index in a list and returns
* a subset of the choices if the list is too long.
*/
var Paginator = module.exports = function () {
this.pointer = 0;
this.lastIndex = 0;
};
Paginator.prototype.paginate = function (output, active, pageSize) {
pageSize = pageSize || 7;
var middleOfList = Math.floor(pageSize / 2);
var lines = output.split('\n');
// Make sure there's enough lines to paginate
if (lines.length <= pageSize) {
return output;
}
// Move the pointer only when the user go down and limit it to the middle of the list
if (this.pointer < middleOfList && this.lastIndex < active && active - this.lastIndex < pageSize) {
this.pointer = Math.min(middleOfList, this.pointer + active - this.lastIndex);
}
this.lastIndex = active;
// Duplicate the lines so it give an infinite list look
var infinite = _.flatten([lines, lines, lines]);
var topIndex = Math.max(0, active + lines.length - this.pointer);
var section = infinite.splice(topIndex, pageSize).join('\n');
return section + '\n' + chalk.dim('(Move up and down to reveal more choices)');
};
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