# forEach方法模型 function forEach(array, action) {
for (let i = 0; i < array.length; i++) {
action(array[i]);
}
}
# filter方法模型 function filter(array, test) {
var passed = [];
for (let i = 0; i < array.length; i++) {
if (test(array[i]))
passed.push(array[i]);
}
}
filter方法需要return
# map 方法模型 function map(array, transform) {
var mapped = [];
for (var i = 0; i < array.length; i++)
mapped.push(transform(array[i]));
return mapped;
}
map方法需要return
# reduce方法模型 function reduce(array, combine, start) {
var current = start;
for (var i = 0; i < array.length; i++)
current = combine(current, array[i]);
return current;
}
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