var animals = [ {name:'Flukkery', species:'rabbit', age:2.8}, {name:'Happy', species:'dog', age:3.2}, {name:'Meomeo', species:'cat', age:1.9}, {name:'Kuchi', species:'dog', age:3.6}, {name:'Shisi', species:'snake', age:3}, {name:'Harold', species:'dog', age:1.3}, {name:'Wowo', species:'snake', age:1.5}, {name:'Qucy', species:'cat', age:3.0}, {name:'Sticky', species:'snake', age:2.1} ] window.onload = (function(){ var list = 'ol'; addElementText('h4','All animals (array)') addElementText('pre', JSON.stringify(animals, null, ' ')) addElementText('h4','All animals (converted to single element array by map function)') addElementlist( list, animals.map(function(animal){ return "Name: " + animal.name + " , Species: " + animal.species})) // addElementlist('li', animals.map(function(animal){ return animal.species })) addElementText('h4','All animals (converted to single table by map function)') addElementTableList( 'tr', animals.map(function(animal){ var row = [] row[0] = animal.name row[1] = animal.species row[2] = animal.age var animalRow = '' + row[0] + '' + row[1] + '' + row[2] + '' return animalRow })) var isSpecies = function(animal) { return animal.species==this // 2nd argument is this } var sel = animals.filter(isSpecies,"dog") addElementText('h4','Select dog (use filter function)') addElementlist( list, sel.map(function(s){ return s.name })) sel = animals.filter(isSpecies,"cat") addElementText('h4','Select cat (use filter function)') addElementlist( list, sel.map(function(s){ return s.name })) sel = animals.filter(isSpecies,"snake") addElementText('h4','Select snake (use filter function)') addElementlist( list, sel.map(function(s){ return s.name })) var isAgeBelow = function(animal) { return animal.age < this // 2nd argument is this } sel = animals.filter(isAgeBelow,"2") addElementText('h4','Age below 2 (use filter function)') addElementlist( list, sel.map(function(s){ return s.name })) var totalAge = animals.reduce(function(sum, animal){ return sum += animal.age },0) averageAge = totalAge / animals.length addElementText('h4','Animal average age (using reduce)') addElementText('p','Total age: ' + totalAge.toFixed(2)) addElementText('p','Average age: ' + averageAge.toFixed(2)) var oldest = animals.reduce(function(max, animal) { if( animal.age>max ) return max = animal.age return max },0) addElementText('h4','Oldest age (using reduce)') addElementText('p','Oldest age: ' + oldest ) var youngest = animals.reduce(function(min, animal) { if( animal.age

How to use function operators: filter, map and reduce