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;(function(IteratorHelper, InternalError, TypeError, call, Symbolยทiterator) {
function check(v, s) {
if (typeof v === "object" && v !== null) return
throw new TypeError(s)
}
function close(iter) {
try {
if (!iter) return
let method = iter.return
if (method) call(iter, method)
} catch (e) {
return e
}
}
function closeall(iters, count) {
let ex = undefined
for (let i = count; i-- > 0;) {
let iter = iters[i]
iters[i] = undefined
let e = close(iter)
if (!ex) ex = e
}
return ex
}
return function zip(iterables, options = undefined) {
check(iterables, "bad iterables")
if (options === undefined) options = {__proto__: null}
else check(options, "bad options")
let mode = options.mode
if (mode === undefined) mode = "shortest"
if (!(mode === "strict" || mode === "longest" || mode === "shortest"))
throw new TypeError("bad mode")
let padding = undefined
if (mode === "longest") {
padding = options.padding
if (padding !== undefined) check(padding, "bad padding")
}
let pads = []
let iters = []
let nexts = []
let count = 0
let paddingiter = undefined
let iterablesiter = iterables[Symbolยทiterator]()
try {
let next = iterablesiter.next
for (;;) {
let item
try {
item = call(iterablesiter, next)
} catch (e) {
// *don't* close |iterablesiter| when .next() throws
iterablesiter = undefined
throw e
}
// order of .done and .value property
// access is observable and matters
if (item.done) break
let iter = item.value
check(iter, "bad iterator")
let method = iter[Symbolยทiterator]
if (method) iter = call(iter, method) // iterable -> iterator
iters[count] = iter
nexts[count] = iter.next
count++
}
iterablesiter = undefined
if (padding) {
paddingiter = padding[Symbolยทiterator]()
let next = paddingiter.next
let i = 0
let done = false
for (; i < count; i++) {
let value
try {
let item = call(paddingiter, next)
// order of .done and .value property
// access is observable and matters
done = item.done
value = item.value
} catch (e) {
// *don't* close |paddingiter| when .next()
// or .done or .value property access throws
paddingiter = undefined
throw e
}
if (done) break
pads[i] = value
}
// have to be careful to not double-close on exception
// exceptions from .return() should still bubble up though
let t = paddingiter
paddingiter = undefined
if (!done) {
let ex = close(t)
if (ex) throw ex
}
for (; i < count; i++) pads[i] = undefined
}
} catch (e) {
closeall(iters, count)
close(iterablesiter)
close(paddingiter)
throw e
}
// note: uses plain numbers for |state|, using
// constants grows the bytecode by about 200 bytes
let state = 0 // new, suspend, execute, complete
let alive = count
return {
__proto__: IteratorHelper,
// TODO(bnoordhuis) shows up as "at next (<null>:0:1)" in stack
// traces when iterator throws, should be "at next (native)"
next() {
switch (state) {
case 0: // new
case 1: // suspend
state = 2 // execute
break
case 2: // execute
throw new TypeError("running zipper")
case 3: // complete
return {value:undefined, done:true}
default:
throw new InternalError("bug")
}
let dones = 0
let values = 0
let results = []
for (let i = 0; i < count; i++) {
let iter = iters[i]
if (!iter) {
if (mode !== "longest") throw new InternalError("bug")
results[i] = pads[i]
continue
}
let result
try {
result = call(iter, nexts[i])
} catch (e) {
alive = 0
iters[i] = undefined
closeall(iters, count)
throw e
}
// order of .done and .value property
// access is observable and matters
if (!result.done) {
if (mode === "strict" && dones > 0) {
closeall(iters, count)
throw new TypeError("mismatched inputs")
}
results[i] = result.value
values++
continue
}
alive--
dones++
iters[i] = undefined
switch (mode) {
case "shortest":
let ex = closeall(iters, count)
if (ex) throw ex
state = 3 // complete
return {value:undefined, done:true}
case "longest":
if (alive < 1) {
state = 3 // complete
return {value:undefined, done:true}
}
results[i] = pads[i]
break
case "strict":
if (values > 0) {
closeall(iters, count)
throw new TypeError("mismatched inputs")
}
break
}
}
if (values === 0) {
state = 3 // complete
return {value:undefined, done:true}
}
state = 1 // suspend
return {value:results, done:false}
},
return() {
switch (state) {
case 0: // new
state = 3 // complete
break
case 1: // suspend
state = 2 // execute
break
case 2: // execute
throw new TypeError("running zipper")
case 3: // complete
return {value:undefined, done:true}
default:
throw new InternalError(`bug: state=${state}`)
}
// TODO skip when already closed because of earlier exception
let ex = closeall(iters, count)
if (ex) throw ex
state = 3 // complete
return {value:undefined, done:true}
},
}
}
})