als-statistics/lib/table/filter.js

A powerful and lightweight JavaScript library for descriptive statistics, regression, clustering, outlier detection, and noise analysis using a flexible table/column architecture.

class ColumnFilter {
   constructor() {
      this.filterState = 0;
      this.init()
   }
   init() {
      this.filtered = {};
      this.maxFilter = 0;
      this.count = 0
   }
   get isFiltered() { return this.count > 0 }

   filterRows(indexes = []) {
      const { count } = this
      for (let i of indexes) {
         if (this.filtered[i]) continue
         this.filtered[i] = true
         this.count++
      }
      if (indexes[indexes.length - 1] > this.maxFilter) this.maxFilter = indexes[indexes.length - 1]
      if (this.count > count) this.filterState++
      return this
   }

   clearRowsFilters(indexes = []) {
      if (this.maxFilter === 0) return
      const { count, maxFilter } = this
      for (let i of indexes) {
         if (!this.filtered[i]) continue
         delete this.filtered[i]
         this.count--
      }
      if (!this.filtered[maxFilter]) { // If `maxFilter` deleted, find new max
         const keys = Object.keys(this.filtered).map(n => Number(n))
         this.maxFilter = keys[keys.length - 1] || 0;
      }
      if (count > this.count) this.filterState++
      return this
   }

   clearAllRowsFilters() { this.init(); this.filterState++; return this }
}

module.exports = ColumnFilter