The Boy Scout Rule

Alistair McKinnell@amckinnell

Nulogy

Imagine that your codebase gets a little

better everyday

It’s up to you

It’s up to you(and your teammates)

The Boy Scout Rule

Always check a module in cleaner than when you checked it out

Know Your Language

def apply_other_filters(params) case params[:has_production] when "yes" conditions = ["produced_uom > 0"] when "no" conditions = ["produced_uom = 0"] else conditions = [] end conditions end

def apply_other_filters(params) case params[:has_production] when "yes" conditions = ["produced_uom > 0"] when "no" conditions = ["produced_uom = 0"] else conditions = [] end conditions end

conditions

conditions

conditions

conditions

def apply_other_filters(params) case params[:has_production] when "yes" ["produced_uom > 0"] when "no" ["produced_uom = 0"] else [] end end

def get_number_of_lines reader = open_csv_reader reader.shift

lines = 0 reader.each do |row| lines += 1 end

lines end

def get_number_of_lines reader = open_csv_reader reader.shift

lines = 0 reader.each do |row| lines += 1 end

lines end

lines = 0 reader.each do |row| lines += 1 end

lines

def get_number_of_lines reader = open_csv_reader reader.shift

end reader.count

def repeat_commas(length) str = "" length.times { |i| str << ',' } str end

def repeat_commas(length) str = "" length.times { |i| str << ',' } str end

str str str

def repeat_commas(length) (1..length).map { ',' }.join end

def repeat_commas(length) ',' * length end

',' * length

def create @organization = Organization.new(org_params)

validate_org :new end

def update load_organization @organization.attributes = org_params

validate_org :edit end

def create @organization = Organization.new(org_params)

validate_org :new end

def update load_organization @organization.attributes = org_params

validate_org :edit end

validate_org :new

validate_org :edit

validate_org(failure_action: :new)

validate_org(failure_action: :edit)

def create @organization = Organization.new(org_params)

end

def update load_organization @organization.attributes = org_params

end

def assign_attributes(product, container) product.code = container.code product.desc = container.desc product.identifier = container.identifier product end

def assign_attributes(product, container) product.code = container.code product.desc = container.desc product.identifier = container.identifier product end

product product product product

def assign_attributes(product, container) product.code = container.code product.desc = container.desc product.identifier = container.identifier product end

def assign_attributes(product, container) product.tap do |p| p.code = container.code p.desc = container.desc p.identifier = container.identifier end end

product product product product product.tap

def assign_attributes(product, container) product.code = container.code product.desc = container.desc product.identifier = container.identifier product end

def assign_attributes(product, container) product.tap do |p| p.code = container.code p.desc = container.desc p.identifier = container.identifier end end

Know Your Language

expect(po_item.due).to eq(time('15-01-01')) expect(po_item.price_per_unit).to eq(19) expect(po_item.quantity).to eq(14)

expect(po_item.due).to eq(time('15-01-01')) expect(po_item.price_per_unit).to eq(19) expect(po_item.quantity).to eq(14)

po_item po_item po_item

expect(po_item.due).to eq(time('15-01-01')) expect(po_item.price_per_unit).to eq(19) expect(po_item.quantity).to eq(14)

expect(po_item).to have_attributes( due: time('15-01-01'), price_per_unit: 19, quantity: 14 )

po_item po_item po_item

po_item

expect(po_item.due).to eq(time('15-01-01')) expect(po_item.price_per_unit).to eq(19) expect(po_item.quantity).to eq(14)

expect(po_item).to have_attributes( due: time('15-01-01'), price_per_unit: 19, quantity: 14 )

Know Your Library

def serializer DEPENDENCIES[type][:serializer] end

def serializer DEPENDENCIES[type][:serializer] end [:serializer]

def serializer DEPENDENCIES[type] end .fetch(:serializer)

Fail Fast

def number "#{order.number}-#{order_item.number}" end

Remove Dead Code

The Boy Scout Rule

Always check a module in cleaner than when you checked it out

Know Your LanguageKnow Your Library

Fail FastRemove Dead Code

When I look at my code from six months ago

I expect to see ways to improve it

Put your learning and understanding back

into the code

It’s up to you