BDAG Lexicon on EGW EIMI (John 8:58)

BDAG page 283d – To establish identity the formula EGW EIMI is oft. used in the gospels (corresp. to Hebr. ANI HU Dt 32:39; Is 43:10), in such a way that the predicate must be understood fr. The context: Mt 14:27; Mk 6:50; 13:6; 14:62 Lk 22:70; J 4:26; 6:20; 8:24, 28; 13:19; 18:5f and oft.; s. on EGW – In a question MHTI EGW EIMI; surely it is not I? Mt 26:22,25.

EGW in BDAG 275a – EGW EIMI it is I (in contrast to others) Mt 14:27; Lk 24:39; J 6:20; I am the man 9:9; w. strong emphasis: I am the one (i.e. the Messiah) Mk 13:6; Lk 21:8; J 8:24, 28; cp. Vs 58.
… --On J 8:58 s. EFreed, JSNT 17,'83

What does the JSNT say?

EFreed, JSNT 17– "I should suggest, rather, that the meaning of the sentence in the mind of the writer was: "Before Abraham was, I, the Christ, the Son of God, existed."