I cannot understand the usage of infinitive in this sentence.
Japan went to save stranded resident and fight flood caused by one of worst typhoon to hit country in recent history.
Please explain why 'to hit' has been used here . Providing any reference material will be appreciated.
The basic rule is that infinitives may follow superlatives, ordinal numbers, and a few other words that have similar functions. This explains why, in your sentence, the infinitive to hit follows the phrase worst typhoon
Michael Swan (Practical English Usage, 2017 edition, section 101) writes the following:
superlatives, etc: the oldest athlete to win . . .
Superlatives can be followed by an infinitive structure. The meaning is similar to an identifying relative clause.
He's the oldest athlete ever to win an Olympic gold medal. (= . . . who has ever won . . .)
This structure is also common with first, second, third, etc, next, last and only.
Who was the first person to climb Everest without oxygen?
The next to arrive was Mrs Patterson.
She's the only scientist to have won three Nobel prizes.
Most of Swan's examples illustrate the words being used as adjectives or determiners. The same rule applies when they are used as nouns:
The first to escape the burning building was Jason Bourne.
The youngest to win the competition was Jack Reacher.
When we say "A" is hit by "B", we mean "B" affects "A".
From Cambridge, one meaning of "hit" that is relevant to your context is
to have an unpleasant or negative effect on a person or thing
Look at these examples:
"Production has been badly hit by the strike." - This means that the strike created negative impacts on production. Due to the strike, factories were closed as workers were on the streets. This stopped production and there were losses.
"Demand for transatlantic flights has been hit by fears of terrorist attacks." - This means that because people were afraid of terrorist attacks, they did not want to travel by plane. The demand for tickets fell, and airline companies incurred severe losses. The demand for tickets was severely "hit" or "impacted" by fears of terrorist attacks.
In your case,
... one of [the] worst typhoons to hit [the] country in recent history.
means that there were several typhoons that happened before, but this one was the worst one. Because there was flood and severe damage to the country, the appropriate word is "hit". The country was badly affected by the typhoon. The impact of the typhoon was too severe.
