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…f needed There is a slight difference between `map`...`concatAll` and `concatMap` in that the latter (`concatMap`) will ensure that the computations are executed in-order and only if needed while the former may execute the `map` body of all items if they do not emit immediately. That is, if the stream is `from([a, b, c]).pipe(map(v => of(v).pipe(delay(1))), concatAll(), first())` the `map` body will execute for all of `a`, `b`, and `c`. However, the following will only execute the `concatMap` body for `a` `from([a, b, c]).pipe(concatMap(v => of(v).pipe(delay(1))), first())` See https://stackblitz.com/edit/rxjs-cvwxyx fixes angular#38691
atscott
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This change contains the test from angular#38780 and also removes `defer` from the `apply_redirects` logic because the change that introduced `concatMap` instead of `map`...`concatAll` makes `defer` unnecessary.
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…f needed (#38780) There is a slight difference between `map`...`concatAll` and `concatMap` in that the latter (`concatMap`) will ensure that the computations are executed in-order and only if needed while the former may execute the `map` body of all items if they do not emit immediately. That is, if the stream is `from([a, b, c]).pipe(map(v => of(v).pipe(delay(1))), concatAll(), first())` the `map` body will execute for all of `a`, `b`, and `c`. However, the following will only execute the `concatMap` body for `a` `from([a, b, c]).pipe(concatMap(v => of(v).pipe(delay(1))), first())` See https://stackblitz.com/edit/rxjs-cvwxyx fixes #38691 PR Close #38780
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…f needed
There is a slight difference between
map...concatAllandconcatMapin that the latter (
concatMap) will ensure that the computations areexecuted in-order and only if needed while the former may execute the
mapbody of all items if they do not emit immediately. That is, if the streamis
from([a, b, c]).pipe(map(v => of(v).pipe(delay(1))), concatAll(), first())the
mapbody will execute for all ofa,b, andc.However, the following will only execute the
concatMapbody forafrom([a, b, c]).pipe(concatMap(v => of(v).pipe(delay(1))), first())See https://stackblitz.com/edit/rxjs-cvwxyx
fixes #38691
Note: rather than using
deferin thecanLoadcomputation, I went withconcatMapto avoid issues with missing thedeferin other places down the line. Note that this is the second time a bug has occurred because the computations of the route may happen immediately (the place I removeddeferfrom in this PR).Also note that
concatMapis already being used in themasterbranch but I will still need to create another PR to add the test from this one tomaster.