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joplin/packages/lib/ArrayUtils.js
2020-11-05 16:58:23 +00:00

84 lines
2.1 KiB
JavaScript

const ArrayUtils = {};
ArrayUtils.unique = function(array) {
return array.filter(function(elem, index, self) {
return index === self.indexOf(elem);
});
};
ArrayUtils.removeElement = function(array, element) {
const index = array.indexOf(element);
if (index < 0) return array;
const newArray = array.slice();
newArray.splice(index, 1);
return newArray;
};
// https://stackoverflow.com/a/10264318/561309
ArrayUtils.binarySearch = function(items, value) {
let startIndex = 0,
stopIndex = items.length - 1,
middle = Math.floor((stopIndex + startIndex) / 2);
while (items[middle] != value && startIndex < stopIndex) {
// adjust search area
if (value < items[middle]) {
stopIndex = middle - 1;
} else if (value > items[middle]) {
startIndex = middle + 1;
}
// recalculate middle
middle = Math.floor((stopIndex + startIndex) / 2);
}
// make sure it's the right value
return items[middle] != value ? -1 : middle;
};
ArrayUtils.findByKey = function(array, key, value) {
for (let i = 0; i < array.length; i++) {
const o = array[i];
if (typeof o !== 'object') continue;
if (o[key] === value) return o;
}
return null;
};
ArrayUtils.contentEquals = function(array1, array2) {
if (array1 === array2) return true;
if (!array1.length && !array2.length) return true;
if (array1.length !== array2.length) return false;
for (let i = 0; i < array1.length; i++) {
const a1 = array1[i];
if (array2.indexOf(a1) < 0) return false;
}
return true;
};
// Merges multiple overlapping intervals into a single interval
// e.g. [0, 25], [20, 50], [75, 100] --> [0, 50], [75, 100]
ArrayUtils.mergeOverlappingIntervals = function(intervals, limit) {
intervals.sort((a, b) => a[0] - b[0]);
const stack = [];
if (intervals.length) {
stack.push(intervals[0]);
for (let i = 1; i < intervals.length && stack.length < limit; i++) {
const top = stack[stack.length - 1];
if (top[1] < intervals[i][0]) {
stack.push(intervals[i]);
} else if (top[1] < intervals[i][1]) {
top[1] = intervals[i][1];
stack.pop();
stack.push(top);
}
}
}
return stack;
};
module.exports = ArrayUtils;